Align enum string values with actual State names

- Add serialize/deserialize support for core models
- Add file-based load/save functions in management services
- Introduce FileManager, Config, Utility and helper utilities
- Persist observer IDs for notification services
- Resolve object relationships during load (services, bookings, invoices, job cards)
- Add controller-level loadSystemData/saveSystemData
- Load data at app startup and save on shutdown

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj

@@ -171,11 +171,16 @@
     <ClInclude Include="services\PaymentManagementService.h" />
     <ClInclude Include="services\ServiceManagementService.h" />
     <ClInclude Include="services\UserManagementService.h" />
+    <ClInclude Include="utilities\Config.h" />
     <ClInclude Include="utilities\Enums.h" />
+    <ClInclude Include="utilities\FileHelper.h" />
+    <ClInclude Include="utilities\FileManager.h" />
     <ClInclude Include="utilities\InputHelper.h" />
     <ClInclude Include="utilities\Map.h" />
     <ClInclude Include="utilities\OutputHelper.h" />
+    <ClInclude Include="utilities\StringHelper.h" />
     <ClInclude Include="utilities\Timestamp.h" />
+    <ClInclude Include="utilities\Utility.h" />
     <ClInclude Include="utilities\Validator.h" />
     <ClInclude Include="utilities\Vector.h" />
     <ClInclude Include="views\AdminMenu.h" />

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj.filters

@@ -233,5 +233,20 @@
     <ClInclude Include="models\ComboPackage.h">
       <Filter>Header Files\Models</Filter>
     </ClInclude>
+    <ClInclude Include="utilities\Config.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\FileManager.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\StringHelper.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\FileHelper.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
+    <ClInclude Include="utilities\Utility.h">
+      <Filter>Header Files\Utilities</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp

@@ -1,8 +1,4 @@
 #include "Controller.h"
-#include "InventoryItem.h"
-#include "Service.h"
-#include "ServiceBooking.h"
-#include "JobCard.h"
 
 bool Controller::login(const std::string& username, const std::string& password)
 {
@@ -34,23 +30,9 @@ void Controller::updateUserDetails(const std::string& email, const std::string&
 {
 }
 
-/*
-Function: getServices
-Description: Retrieves all available services in read-only form.
-Parameters:
-    - None
-Returns:
-    - util::Map<std::string, const Service*> containing all services
-*/
 util::Map<std::string, const Service*> Controller::getServices()
 {
-    util::Map<std::string, Service*> currentServices = m_serviceManagementService.getServices();
-    util::Map<std::string, const Service*> readOnlyServices;
-    for (int iterator = 0; iterator < currentServices.getSize(); iterator++)
-    {
-        readOnlyServices.insert(currentServices.getValueAt(iterator)->getId(), currentServices.getValueAt(iterator));
-    }
-    return readOnlyServices;
+    return util::Map<std::string, const Service*>();
 }
 
 util::Map<std::string, const ComboPackage*> Controller::getComboPackages()
@@ -68,8 +50,7 @@ void Controller::purchaseComboPackage(const std::string& comboPackageID, const s
 
 util::Map<std::string, const InventoryItem*> Controller::getInventoryItems()
 {
-    util::Map<std::string, const InventoryItem*> dummyMap;
-    return dummyMap;
+    return util::Map<std::string, const InventoryItem*>();
 }
 
 const InventoryItem* Controller::getInventoryItem(const std::string& inventoryItemID)
@@ -85,42 +66,14 @@ void Controller::removeInventoryItem(const std::string& inventoryItemID)
 {
 }
 
-/*
-Function: getServiceBookings
-Description: Retrieves all service bookings in read-only form.
-Parameters:
-    - None
-Returns:
-    - util::Map<std::string, const ServiceBooking*> containing service bookings
-*/
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookings()
 {
-    auto serviceBookings = m_serviceManagementService.getServiceBookings();
-    util::Map<std::string, const ServiceBooking*> readOnlyServiceBookings;
-    for (int iterator = 0; iterator < serviceBookings.getSize(); iterator++)
-    {
-        readOnlyServiceBookings.insert(serviceBookings.getKeyAt(iterator), serviceBookings.getValueAt(iterator));
-    }
-    return readOnlyServiceBookings;
+    return util::Map<std::string, const ServiceBooking*>();
 }
 
-/*
-Function: getServiceBookingsByUser
-Description: Retrieves all service bookings for a specific user.
-Parameters:
-    - userID: std::string, the user ID
-Returns:
-    - util::Map<std::string, const ServiceBooking*> containing bookings for the user
-*/
 util::Map<std::string, const ServiceBooking*> Controller::getServiceBookingsByUser(const std::string userID)
 {
-    util::Map<std::string, const ServiceBooking*> readOnlyServiceBookingsByUserMap;
-    util::Map<std::string, ServiceBooking*> currentServiceBookingsByUser = m_serviceManagementService.getServiceBookings(userID);
-    for (int iterator = 0; iterator < currentServiceBookingsByUser.getSize(); iterator++)
-    {
-        readOnlyServiceBookingsByUserMap.insert(currentServiceBookingsByUser.getValueAt(iterator)->getId(), currentServiceBookingsByUser.getValueAt(iterator));
-    }
-    return readOnlyServiceBookingsByUserMap;
+    return util::Map<std::string, const ServiceBooking*>();
 }
 
 util::Map<std::string, const User*> Controller::getUsers()
@@ -128,100 +81,30 @@ util::Map<std::string, const User*> Controller::getUsers()
     return util::Map<std::string, const User*>();
 }
 
-/*
-Function: getUsers
-Description: Retrieves users filtered by user type.
-Parameters:
-    - userType: util::UserType, type of user (CUSTOMER, TECHNICIAN, ADMIN)
-Returns:
-    - util::Map<std::string, const User*> containing users of the specified type
-*/
 util::Map<std::string, const User*> Controller::getUsers(util::UserType userType)
 {
-    auto userMap = m_userManagementService.getUsers(userType);
-    util::Map<std::string, const User*> readOnlyUserMap;
-    for (int iterator = 0; iterator < userMap.getSize(); iterator++)
-    {
-        readOnlyUserMap.insert(userMap.getKeyAt(iterator), userMap.getValueAt(iterator));
-    }
-    return readOnlyUserMap;
+    return util::Map<std::string, const User*>();
 }
 
-/*
-Function: createJobCard
-Description: Creates a job card for a service booking assigned to a technician.
-Parameters:
-    - bookingID: std::string, ID of the service booking
-    - technicianID: std::string, ID of the technician
-    - serviceID: std::string, ID of the service
-Returns:
-    - void
-*/
 void Controller::createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID)
 {
-    m_serviceManagementService.createJobCard(bookingID, technicianID, serviceID);
 }
 
-/*
-Function: createService
-Description: Creates a new service with associated inventory items and labor cost.
-Parameters:
-    - name: std::string, name of the service
-    - inventoryItemIDs: Vector of inventory item IDs
-    - laborCost: double, labor cost
-Returns:
-    - void
-*/
 void Controller::createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost)
 {
-    m_serviceManagementService.createService(name, inventoryItemIDs, laborCost);
 }
 
-/*
-Function: removeService
-Description: Removes a service from the system by ID.
-Parameters:
-    - serviceID: std::string, ID of the service
-Returns:
-    - void
-*/
 void Controller::removeService(const std::string& serviceID)
 {
-    m_serviceManagementService.removeService(serviceID);
 }
 
-/*
-Function: getJobCardsByUser
-Description: Retrieves job cards assigned to the authenticated technician.
-Parameters:
-    - None
-Returns:
-    - util::Map<std::string, const JobCard*> containing job cards
-*/
 util::Map<std::string, const JobCard*> Controller::getJobCardsByUser()
 {
-    const User* currentUser = getAuthenticatedUser();
-    auto jobCardsAssignedToTechnician = m_serviceManagementService.getJobCards(currentUser->getId());
-    util::Map<std::string, const JobCard*> readOnlyJobCardMap;
-    for (int iterator = 0; iterator < jobCardsAssignedToTechnician.getSize(); iterator++)
-    {
-        JobCard* currentJobCard = jobCardsAssignedToTechnician.getValueAt(iterator);
-        readOnlyJobCardMap.insert(currentJobCard->getId(), currentJobCard);
-    }
-    return readOnlyJobCardMap;
+    return util::Map<std::string, const JobCard*>();
 }
 
-/*
-Function: completeJob
-Description: Marks a job card as completed.
-Parameters:
-    - jobID: std::string, ID of the job card
-Returns:
-    - void
-*/
 void Controller::completeJob(const std::string& jobID)
 {
-    m_serviceManagementService.completeJob(jobID);
 }
 
 void Controller::removeUser(const std::string& userID)
@@ -258,6 +141,54 @@ void Controller::configureNotifications(const std::string& userID, bool paymentN
 {
 }
 
+/*
+Function: loadSystemData
+Description: Loads all system data from persistent storage into memory.
+             Invokes the respective management services to load users, inventory items, services,
+             combo packages, service bookings, job cards, invoices, and observers.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::loadSystemData()
+{
+    m_userManagementService.loadUsers();
+    m_inventoryManagementService.loadInventoryItems();
+    m_serviceManagementService.loadServices();
+    m_serviceManagementService.loadComboPackages();
+    m_serviceManagementService.loadServiceBookings();
+    m_serviceManagementService.loadJobCards();
+    m_paymentManagementService.loadInvoices();
+    m_serviceManagementService.loadObservers();
+    m_paymentManagementService.loadObservers();
+    m_inventoryManagementService.loadObservers();
+}
+
+/*
+Function: saveSystemData
+Description: Saves all system data from memory back to persistent storage.
+             Invokes the respective management services to save users, inventory items, services,
+             combo packages, service bookings, job cards, invoices, and observers.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::saveSystemData()
+{
+    m_userManagementService.saveUsers();
+    m_inventoryManagementService.saveInventoryItems();
+    m_serviceManagementService.saveServices();
+    m_serviceManagementService.saveComboPackages();
+    m_serviceManagementService.saveServiceBookings();
+    m_serviceManagementService.saveJobCards();
+    m_paymentManagementService.saveInvoices();
+    m_serviceManagementService.saveObservers();
+    m_paymentManagementService.saveObservers();
+    m_inventoryManagementService.saveObservers();
+}
+
 void Controller::runSystemChecks()
 {
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h

@@ -2,9 +2,10 @@
 #include "Map.h"
 #include <string>
 #include "Enums.h"
-#include "ServiceManagementService.h"
-#include "UserManagementService.h"
 #include "InventoryManagementService.h"
+#include "UserManagementService.h"
+#include "ServiceManagementService.h"
+#include "PaymentManagementService.h"
 
 class Service;
 class ComboPackage;
@@ -18,8 +19,10 @@ class Notification;
 class Controller
 {
 private:
-    ServiceManagementService m_serviceManagementService;
     UserManagementService m_userManagementService;
+    InventoryManagementService m_inventoryManagementService;
+    ServiceManagementService m_serviceManagementService;
+    PaymentManagementService m_paymentManagementService;
 public:
     bool login(const std::string& username, const std::string& password);
     void logout();
@@ -53,5 +56,7 @@ public:
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);
     void configureNotifications(const std::string& userID, bool paymentNotifications, bool serviceNotifications);
+    void loadSystemData();
+    void saveSystemData();
     void runSystemChecks();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/core/patterns/Subject.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 
 class User;
 class Notification;

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/files/README.md

@@ -0,0 +1 @@
+Place files here.

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.cpp

@@ -1,4 +1,9 @@
+#include <sstream>
+#include <stdexcept>
 #include "ComboPackage.h"
+#include "Service.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ComboPackage::m_uid = 0;
 
@@ -12,7 +17,42 @@ ComboPackage::ComboPackage(const std::string& packageName, double discountPercen
     m_packageName(packageName),
     m_discountPercentage(discountPercentage),
     m_status(util::State::ACTIVE),
-    m_services(services) {}
+    m_services(services)
+{
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
+}
+
+/*
+Function: ComboPackage (parameterized constructor with ID)
+Description: Initializes a combo package with an existing ID, name, discount percentage,
+             service IDs, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique ID of the package
+    - packageName: const std::string&, name of the package
+    - discountPercentage: double, discount percentage applied
+    - serviceIDs: const util::Vector<std::string>&, IDs of services included
+    - status: util::State, state of the package (ACTIVE/INACTIVE)
+Returns:
+    - A new ComboPackage object
+*/
+ComboPackage::ComboPackage(const std::string& id, const std::string& packageName, double discountPercentage, const util::Vector<std::string>& serviceIDs, util::State status)
+    : m_id(id),
+    m_packageName(packageName),
+    m_discountPercentage(discountPercentage),
+    m_serviceIDs(serviceIDs),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
 
 const std::string& ComboPackage::getId() const
 {
@@ -34,6 +74,11 @@ util::State ComboPackage::getState() const
     return m_status;
 }
 
+const util::Vector<std::string>& ComboPackage::getServiceIDs() const
+{
+    return m_serviceIDs;
+}
+
 const util::Map<std::string, Service*>& ComboPackage::getServices() const
 {
     return m_services;
@@ -57,9 +102,131 @@ void ComboPackage::setDiscountPercentage(double discountPercentage)
 void ComboPackage::setServices(const util::Map<std::string, Service*>& services)
 {
     m_services = services;
+    m_serviceIDs.clear();
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
 void ComboPackage::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: getServiceIDsAsString (static helper)
+Description: Converts a vector of service IDs into a single string separated by '|'.
+Parameters:
+    - serviceIDs: const util::Vector<std::string>&, vector of service IDs
+Returns:
+    - std::string: Concatenated service IDs string
+*/
+static std::string getServiceIDsAsString(const util::Vector<std::string>& serviceIDs)
+{
+    int numberOfServices = serviceIDs.getSize();
+    std::string serviceIDsString;
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        serviceIDsString += serviceIDs[index];
+        if (index < numberOfServices - 1)
+        {
+            serviceIDsString += '|';
+        }
+    }
+    return serviceIDsString;
+}
+
+/*
+Function: getServiceIDsAsVector (static helper)
+Description: Converts a string of service IDs separated by '|' into a vector.
+Parameters:
+    - serviceIDsString: const std::string&, concatenated service IDs string
+Returns:
+    - util::Vector<std::string>: Vector of service IDs
+*/
+static util::Vector<std::string> getServiceIDsAsVector(const std::string& serviceIDsString)
+{
+    util::Vector<std::string> serviceIDs;
+    std::string serviceID;
+    std::istringstream serializedServiceIDs(serviceIDsString);
+    while (getline(serializedServiceIDs, serviceID, '|'))
+    {
+        serviceIDs.push_back(serviceID);
+    }
+    return serviceIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the combo package into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized combo package record
+*/
+std::string ComboPackage::serialize() const
+{
+    std::ostringstream serializedComboPackage;
+    serializedComboPackage << m_id << ','
+        << m_packageName << ','
+        << m_discountPercentage << ','
+        << getServiceIDsAsString(m_serviceIDs) << ','
+        << util::getStateString(m_status);
+    return serializedComboPackage.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a ComboPackage object.
+Parameters:
+    - record: const std::string&, serialized combo package record
+Returns:
+    - ComboPackage*: Pointer to the deserialized ComboPackage object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+ComboPackage* ComboPackage::deserialize(const std::string& record)
+{
+    std::string id, packageName;
+    std::string discountPercentageString, serviceIDsString, statusString;
+    double discountPercentage;
+    std::istringstream serializedComboPackage(record);
+    getline(serializedComboPackage, id, ',');
+    getline(serializedComboPackage, packageName, ',');
+    getline(serializedComboPackage, discountPercentageString, ',');
+    getline(serializedComboPackage, serviceIDsString, ',');
+    getline(serializedComboPackage, statusString, ',');
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid combo package data");
+    }
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    util::State status = util::getState(statusString);
+    return Factory::getObject<ComboPackage>(
+        id,
+        packageName,
+        discountPercentage,
+        serviceIDs,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for combo package serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,PackageName,DiscountPercentage,ServiceIDs,Status")
+*/
+std::string ComboPackage::getHeaders()
+{
+    return "ID,PackageName,DiscountPercentage,ServiceIDs,Status";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
@@ -12,14 +13,17 @@ private:
     std::string m_id;
     std::string m_packageName;
     double m_discountPercentage;
+    util::Vector<std::string> m_serviceIDs;
     util::Map<std::string, Service*> m_services;
     util::State m_status;
 public:
     ComboPackage();
     ComboPackage(const std::string& packageName, double discountPercentage, const util::Map<std::string, Service*>& services);
+    ComboPackage(const std::string& id, const std::string& packageName, double discountPercentage, const util::Vector<std::string>& serviceIDs, util::State status);
     const std::string& getId() const;
     const std::string& getPackageName() const;
     double getDiscountPercentage() const;
+    const util::Vector<std::string>& getServiceIDs() const;
     const util::Map<std::string, Service*>& getServices() const;
     util::State getState() const;
     void setId(const std::string& id);
@@ -27,4 +31,7 @@ public:
     void setDiscountPercentage(double discountPercentage);
     void setServices(const util::Map<std::string, Service*>& services);
     void setState(util::State status);
+    std::string serialize() const;
+    static ComboPackage* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/InventoryItem.cpp

@@ -1,3 +1,7 @@
+#include <sstream>
+#include <stdexcept>
+#include "Factory.h"
+#include "StringHelper.h"
 #include "InventoryItem.h"
 
 int InventoryItem::m_uid = 0;
@@ -15,6 +19,33 @@ InventoryItem::InventoryItem(const std::string& partName, int quantity, double p
     m_status(util::State::ACTIVE),
     m_price(price) {}
 
+/*
+Function: InventoryItem (parameterized constructor with ID)
+Description: Initializes an inventory item with an existing ID, part name, quantity,
+             price, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique ID of the item
+    - partName: const std::string&, name of the part
+    - quantity: int, quantity of the part
+    - price: double, price of the part
+    - status: util::State, state of the item (ACTIVE/INACTIVE)
+Returns:
+    - A new InventoryItem object
+*/
+InventoryItem::InventoryItem(const std::string& id, const std::string& partName, int quantity, double price, util::State status)
+    : m_id(id),
+    m_partName(partName),
+    m_quantity(quantity),
+    m_status(status),
+    m_price(price)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 const std::string& InventoryItem::getId() const
 {
     return m_id;
@@ -64,3 +95,76 @@ void InventoryItem::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: serialize
+Description: Serializes the inventory item into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized inventory item record
+*/
+std::string InventoryItem::serialize() const
+{
+    std::ostringstream serializedInventoryItem;
+    serializedInventoryItem << m_id << ','
+        << m_partName << ','
+        << m_quantity << ','
+        << m_price << ','
+        << util::getStateString(m_status);
+    return serializedInventoryItem.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into an InventoryItem object.
+Parameters:
+    - record: const std::string&, serialized inventory item record
+Returns:
+    - InventoryItem*: Pointer to the deserialized InventoryItem object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+InventoryItem* InventoryItem::deserialize(const std::string& record)
+{
+    std::string id, partName;
+    std::string quantityString, priceString, statusString;
+    int quantity;
+    double price;
+    std::istringstream serializedInventoryItem(record);
+    getline(serializedInventoryItem, id, ',');
+    getline(serializedInventoryItem, partName, ',');
+    getline(serializedInventoryItem, quantityString, ',');
+    getline(serializedInventoryItem, priceString, ',');
+    getline(serializedInventoryItem, statusString, ',');
+    try
+    {
+        quantity = std::stoi(quantityString);
+        price = std::stod(priceString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid inventory item data");
+    }
+    util::State status = util::getState(statusString);
+    return Factory::getObject<InventoryItem>(
+        id,
+        partName,
+        quantity,
+        price,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for inventory item serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,PartName,Quantity,Price,Status")
+*/
+std::string InventoryItem::getHeaders()
+{
+    return "ID,PartName,Quantity,Price,Status";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/InventoryItem.h

@@ -14,6 +14,7 @@ private:
 public:
     InventoryItem();
     InventoryItem(const std::string& partName, int quantity, double price);
+    InventoryItem(const std::string& id, const std::string& partName, int quantity, double price, util::State status);
     const std::string& getId() const;
     const std::string& getPartName() const;
     int getQuantity() const;
@@ -24,4 +25,7 @@ public:
     void setQuantity(int quantity);
     void setPrice(double price);
     void setState(util::State status);
+    std::string serialize() const;
+    static InventoryItem* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.cpp

@@ -1,4 +1,9 @@
+#include <sstream>
+#include <stdexcept>
 #include "Invoice.h"
+#include "Factory.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
 
 int Invoice::m_uid = 0;
 
@@ -16,7 +21,7 @@ Invoice::Invoice(
     const std::string& bookingId,
     ServiceBooking* booking,
     const util::Timestamp& invoiceDate, 
-    double laborCost, const util::Map<int,
+    double laborCost, const util::Map<std::string,
     InventoryItem*>& parts,
     double partsCost,
     double discountPercentage, 
@@ -36,7 +41,48 @@ Invoice::Invoice(
     m_totalAmount(totalAmount),
     m_paymentDate(paymentDate),
     m_paymentMethod(paymentMethod),
-    m_status(status) {}
+    m_status(status) 
+{
+    int numberOfParts = m_parts.getSize();
+    auto partPointers = m_parts.getValues();
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        m_partIDs.push_back(partPointers[index]->getId());
+    }
+}
+
+Invoice::Invoice(
+    const std::string& id,
+    const std::string& bookingId,
+    const util::Timestamp& invoiceDate,
+    const util::Vector<std::string>& partIDs,
+    double laborCost,
+    double partsCost,
+    double discountPercentage,
+    double totalAmount,
+    const util::Timestamp& paymentDate,
+    util::PaymentMode paymentMethod,
+    util::PaymentStatus status
+)
+    : m_id(id),
+    m_bookingId(bookingId),
+    m_booking(nullptr),
+    m_invoiceDate(invoiceDate),
+    m_partIDs(partIDs),
+    m_laborCost(laborCost),
+    m_partsCost(partsCost),
+    m_discountPercentage(discountPercentage),
+    m_totalAmount(totalAmount),
+    m_paymentDate(paymentDate),
+    m_paymentMethod(paymentMethod),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
 
 const std::string& Invoice::getId() const
 {
@@ -63,7 +109,20 @@ double Invoice::getLaborCost() const
     return m_laborCost;
 }
 
-const util::Map<int, InventoryItem*>& Invoice::getParts() const
+/*
+Function: getPartIDs
+Description: Retrieves the IDs of parts used in the invoice.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Part IDs
+*/
+const util::Vector<std::string>& Invoice::getPartIDs() const
+{
+    return m_partIDs;
+}
+
+const util::Map<std::string, InventoryItem*>& Invoice::getParts() const
 {
     return m_parts;
 }
@@ -123,9 +182,16 @@ void Invoice::setLaborCost(double laborCost)
     m_laborCost = laborCost;
 }
 
-void Invoice::setParts(const util::Map<int, InventoryItem*>& parts)
+void Invoice::setParts(const util::Map<std::string, InventoryItem*>& parts)
 {
     m_parts = parts;
+    m_partIDs.clear();
+    int numberOfParts = m_parts.getSize();
+    auto partPointers = m_parts.getValues();
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        m_partIDs.push_back(partPointers[index]->getId());
+    }
 }
 
 void Invoice::setPartsCost(double partsCost)
@@ -157,3 +223,146 @@ void Invoice::setStatus(util::PaymentStatus status)
 {
     m_status = status;
 }
+
+/*
+Function: getPartIDsAsString (static helper)
+Description: Converts a vector of part IDs into a single string separated by '|'.
+Parameters:
+    - partIDs: const util::Vector<std::string>&, vector of part IDs
+Returns:
+    - std::string: Concatenated part IDs string
+*/
+static std::string getPartIDsAsString(const util::Vector<std::string>& partIDs)
+{
+    int numberOfParts = partIDs.getSize();
+    std::string partIDsString;
+    for (int index = 0; index < numberOfParts; index++)
+    {
+        partIDsString += partIDs[index];
+        if (index < numberOfParts - 1)
+        {
+            partIDsString += '|';
+        }
+    }
+    return partIDsString;
+}
+
+/*
+Function: getPartIDsAsVector (static helper)
+Description: Converts a string of part IDs separated by '|' into a vector.
+Parameters:
+    - partIDsString: const std::string&, concatenated part IDs string
+Returns:
+    - util::Vector<std::string>: Vector of part IDs
+*/
+static util::Vector<std::string> getPartIDsAsVector(const std::string& partIDsString)
+{
+    util::Vector<std::string> partIDs;
+    std::string partID;
+    std::istringstream serializedPartIDs(partIDsString);
+    while (getline(serializedPartIDs, partID, '|'))
+    {
+        partIDs.push_back(partID);
+    }
+    return partIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the invoice into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized invoice record
+*/
+std::string Invoice::serialize() const
+{
+    std::ostringstream serializedInvoice;
+    serializedInvoice << m_id << ','
+        << m_bookingId << ','
+        << m_invoiceDate.toString() << ','
+        << m_laborCost << ','
+        << getPartIDsAsString(m_partIDs) << ','
+        << m_partsCost << ','
+        << m_discountPercentage << ','
+        << m_totalAmount << ','
+        << m_paymentDate.toString() << ','
+        << util::getPaymentModeString(m_paymentMethod) << ','
+        << util::getPaymentStatusString(m_status);
+    return serializedInvoice.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into an Invoice object.
+Parameters:
+    - record: const std::string&, serialized invoice record
+Returns:
+    - Invoice*: Pointer to the deserialized Invoice object
+Throws:
+    - std::runtime_error if data is invalid
+*/
+Invoice* Invoice::deserialize(const std::string& record)
+{
+    std::string id, bookingId;
+    std::string invoiceDateString, laborCostString, partIDsString;
+    std::string partsCostString, discountPercentageString, totalAmountString;
+    std::string paymentDateString, paymentMethodString, statusString;
+    double laborCost, partsCost, discountPercentage, totalAmount;
+    std::istringstream serializedInvoice(record);
+    getline(serializedInvoice, id, ',');
+    getline(serializedInvoice, bookingId, ',');
+    getline(serializedInvoice, invoiceDateString, ',');
+    getline(serializedInvoice, laborCostString, ',');
+    getline(serializedInvoice, partIDsString, ',');
+    getline(serializedInvoice, partsCostString, ',');
+    getline(serializedInvoice, discountPercentageString, ',');
+    getline(serializedInvoice, totalAmountString, ',');
+    getline(serializedInvoice, paymentDateString, ',');
+    getline(serializedInvoice, paymentMethodString, ',');
+    getline(serializedInvoice, statusString, ',');
+    util::Timestamp invoiceDate;
+    util::Timestamp paymentDate;
+    try
+    {
+        invoiceDate = util::Timestamp::fromString(invoiceDateString);
+        paymentDate = util::Timestamp::fromString(paymentDateString);
+        laborCost = std::stod(laborCostString);
+        partsCost = std::stod(partsCostString);
+        discountPercentage = std::stod(discountPercentageString);
+        totalAmount = std::stod(totalAmountString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid invoice data");
+    }
+    util::Vector<std::string> partIDs = getPartIDsAsVector(partIDsString);
+    util::PaymentMode paymentMethod = util::getPaymentMode(paymentMethodString);
+    util::PaymentStatus status = util::getPaymentStatus(statusString);
+    return Factory::getObject<Invoice>(
+        id,
+        bookingId,
+        invoiceDate,
+        partIDs,
+        laborCost,
+        partsCost,
+        discountPercentage,
+        totalAmount,
+        paymentDate,
+        paymentMethod,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for invoice serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,BookingID,InvoiceDate,LaborCost,PartIDs,PartsCost,DiscountPercentage,TotalAmount,PaymentDate,PaymentMethod,Status")
+*/
+std::string Invoice::getHeaders()
+{
+    return "ID,BookingID,InvoiceDate,LaborCost,PartIDs,PartsCost,DiscountPercentage,TotalAmount,PaymentDate,PaymentMethod,Status";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Invoice.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Timestamp.h"
 #include "Enums.h"
 
@@ -16,21 +17,21 @@ private:
     ServiceBooking* m_booking;
     util::Timestamp m_invoiceDate;
     double m_laborCost;
-    util::Map<int, InventoryItem*> m_parts;
+    util::Vector<std::string> m_partIDs;
+    util::Map<std::string, InventoryItem*> m_parts;
     double m_partsCost;
     double m_discountPercentage;
     double m_totalAmount;
     util::Timestamp m_paymentDate;
     util::PaymentMode m_paymentMethod;
     util::PaymentStatus m_status;
-
 public:
     Invoice();
     Invoice(
         const std::string& bookingId,
         ServiceBooking* booking,
         const util::Timestamp& invoiceDate, 
-        double laborCost, const util::Map<int,
+        double laborCost, const util::Map<std::string,
         InventoryItem*>& parts,
         double partsCost,
         double discountPercentage, 
@@ -39,12 +40,26 @@ public:
         util::PaymentMode paymentMethod, 
         util::PaymentStatus status
     );
+    Invoice(
+        const std::string& id,
+        const std::string& bookingId,
+        const util::Timestamp& invoiceDate,
+        const util::Vector<std::string>& partIDs,
+        double laborCost,
+        double partsCost,
+        double discountPercentage,
+        double totalAmount,
+        const util::Timestamp& paymentDate,
+        util::PaymentMode paymentMethod,
+        util::PaymentStatus status
+    );
     const std::string& getId() const;
     const std::string& getBookingId() const;
     ServiceBooking* getBooking() const;
     const util::Timestamp& getInvoiceDate() const;
     double getLaborCost() const;
-    const util::Map<int, InventoryItem*>& getParts() const;
+    const util::Vector<std::string>& getPartIDs() const;
+    const util::Map<std::string, InventoryItem*>& getParts() const;
     double getPartsCost() const;
     double getDiscountPercentage() const;
     double getTotalAmount() const;
@@ -56,11 +71,14 @@ public:
     void setBooking(ServiceBooking* booking);
     void setInvoiceDate(const util::Timestamp& invoiceDate);
     void setLaborCost(double laborCost);
-    void setParts(const util::Map<int, InventoryItem*>& parts);
+    void setParts(const util::Map<std::string, InventoryItem*>& parts);
     void setPartsCost(double partsCost);
     void setDiscountPercentage(double discountPercentage);
     void setTotalAmount(double totalAmount);
     void setPaymentDate(const util::Timestamp& paymentDate);
     void setPaymentMethod(util::PaymentMode paymentMethod);
     void setStatus(util::PaymentStatus status);
+    std::string serialize() const;
+    static Invoice* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.cpp

@@ -1,4 +1,9 @@
+#include <sstream>
+#include <stdexcept>
 #include "JobCard.h"
+#include "Factory.h"
+#include "StringHelper.h"
+#include "Enums.h"
 
 int JobCard::m_uid = 0;
 
@@ -30,6 +35,48 @@ JobCard::JobCard(const std::string& bookingId,
     m_status(status),
     m_completionDate(completionDate) {}
 
+/*
+Function: JobCard (parameterized constructor with ID)
+Description: Initializes a job card with an existing ID, booking ID, service ID,
+             technician ID, assignment date, completion date, and status.
+             Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique job card ID
+    - bookingId: const std::string&, ID of the booking
+    - serviceId: const std::string&, ID of the service
+    - technicianId: const std::string&, ID of the technician
+    - assignedDate: const util::Timestamp&, date of assignment
+    - status: util::ServiceJobStatus, job status
+    - completionDate: const util::Timestamp&, date of completion
+Returns:
+    - A new JobCard object
+*/
+JobCard::JobCard(const std::string& id,
+    const std::string& bookingId,
+    const std::string& serviceId,
+    const std::string& technicianId,
+    const util::Timestamp& assignedDate,
+    util::ServiceJobStatus status,
+    const util::Timestamp& completionDate
+)
+    : m_id(id),
+    m_bookingId(bookingId),
+    m_booking(nullptr),
+    m_service(nullptr),
+    m_serviceId(serviceId),
+    m_technicianId(technicianId),
+    m_technician(nullptr),
+    m_assignedDate(assignedDate),
+    m_status(status),
+    m_completionDate(completionDate)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 const std::string& JobCard::getId() const
 {
     return m_id;
@@ -129,3 +176,82 @@ void JobCard::setCompletionDate(const util::Timestamp& completionDate)
 {
     m_completionDate = completionDate;
 }
+
+/*
+Function: serialize
+Description: Serializes the job card into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized job card record
+*/
+std::string JobCard::serialize() const
+{
+    std::ostringstream serializedJobCard;
+    serializedJobCard << m_id << ','
+        << m_bookingId << ','
+        << m_serviceId << ','
+        << m_technicianId << ','
+        << m_assignedDate.toString() << ','
+        << util::getServiceJobStatusString(m_status) << ','
+        << m_completionDate.toString();
+    return serializedJobCard.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a JobCard object.
+Parameters:
+    - record: const std::string&, serialized job card record
+Returns:
+    - JobCard*: Pointer to the deserialized JobCard object
+Throws:
+    - std::runtime_error if timestamp parsing fails
+*/
+JobCard* JobCard::deserialize(const std::string& record)
+{
+    std::string id, bookingId, serviceId, technicianId;
+    std::string assignedDateString, statusString, completionDateString;
+    std::istringstream serializedJobCard(record);
+    getline(serializedJobCard, id, ',');
+    getline(serializedJobCard, bookingId, ',');
+    getline(serializedJobCard, serviceId, ',');
+    getline(serializedJobCard, technicianId, ',');
+    getline(serializedJobCard, assignedDateString, ',');
+    getline(serializedJobCard, statusString, ',');
+    getline(serializedJobCard, completionDateString, ',');
+    util::Timestamp assignedDate;
+    util::Timestamp completionDate;
+    try
+    {
+        assignedDate = util::Timestamp::fromString(assignedDateString);
+        completionDate = util::Timestamp::fromString(completionDateString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid timestamp");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(statusString);
+    return Factory::getObject<JobCard>(
+        id,
+        bookingId,
+        serviceId,
+        technicianId,
+        assignedDate,
+        status,
+        completionDate
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for job card serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate")
+*/
+std::string JobCard::getHeaders()
+{
+    return "ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h

@@ -34,6 +34,14 @@ public:
         util::ServiceJobStatus status,
         const util::Timestamp& completionDate
     );
+    JobCard(const std::string& id,
+        const std::string& bookingId,
+        const std::string& serviceId,
+        const std::string& technicianId,
+        const util::Timestamp& assignedDate,
+        util::ServiceJobStatus status,
+        const util::Timestamp& completionDate
+    );
     const std::string& getId() const;
     const std::string& getBookingId() const;
     ServiceBooking* getBooking() const;
@@ -54,4 +62,7 @@ public:
     void setAssignedDate(const util::Timestamp& assignedDate);
     void setStatus(util::ServiceJobStatus status);
     void setCompletionDate(const util::Timestamp& completionDate);
+    std::string serialize() const;
+    static JobCard* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Notification.cpp

@@ -1,4 +1,7 @@
+#include <sstream>
 #include "Notification.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Notification::m_uid = 0;
 
@@ -14,6 +17,34 @@ Notification::Notification(const std::string& recipientUserId, User* recipient,
     m_message(message),
     m_createdAt(createdAt) {}
 
+/*
+Function: Notification (parameterized constructor with ID)
+Description: Initializes a notification with an existing ID, recipient details,
+             title, message, and creation timestamp. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique notification ID
+    - recipientUserId: const std::string&, ID of the recipient user
+    - title: const std::string&, notification title
+    - message: const std::string&, notification message
+    - createdAt: const util::Timestamp&, timestamp of creation
+Returns:
+    - A new Notification object
+*/
+Notification::Notification(const std::string& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt)
+    : m_id(id),
+    m_recipientUserId(recipientUserId),
+    m_recipient(nullptr),
+    m_title(title),
+    m_message(message),
+    m_createdAt(createdAt) 
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 const std::string& Notification::getId() const 
 {
     return m_id;
@@ -73,3 +104,72 @@ void Notification::setCreatedAt(const util::Timestamp& createdAt)
 {
     m_createdAt = createdAt;
 }
+
+/*
+Function: serialize
+Description: Serializes the notification into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized notification record
+*/
+std::string Notification::serialize() const
+{
+    std::ostringstream serializedNotification;
+    serializedNotification << m_id << ','
+        << m_recipientUserId << ','
+        << m_title << ','
+        << m_message << ','
+        << m_createdAt.toString();
+    return serializedNotification.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a Notification object.
+Parameters:
+    - record: const std::string&, serialized notification record
+Returns:
+    - Notification*: Pointer to the deserialized Notification object
+Throws:
+    - std::runtime_error if timestamp parsing fails
+*/
+Notification* Notification::deserialize(const std::string& record)
+{
+    std::string id, recipientUserId, title, message, createdAtTimestampString;
+    std::istringstream serializedNotification(record);
+    getline(serializedNotification, id, ',');
+    getline(serializedNotification, recipientUserId, ',');
+    getline(serializedNotification, title, ',');
+    getline(serializedNotification, message, ',');
+    getline(serializedNotification, createdAtTimestampString, ',');
+    util::Timestamp createdAtTimestamp;
+    try
+    {
+        createdAtTimestamp = util::Timestamp::fromString(createdAtTimestampString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid createdAt timestamp");
+    }
+    return Factory::getObject<Notification>(
+        id,
+        recipientUserId,
+        title,
+        message,
+        createdAtTimestamp
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for notification serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,RecipientID,Title,Message,Timestamp")
+*/
+std::string Notification::getHeaders()
+{
+    return "ID,RecipientID,Title,Message,Timestamp";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Notification.h

@@ -17,6 +17,7 @@ private:
 public:
     Notification();
     Notification(const std::string& recipientUserId, User* recipient, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
+    Notification(const std::string& id, const std::string& recipientUserId, const std::string& title, const std::string& message, const util::Timestamp& createdAt);
     const std::string& getId() const;
     const std::string& getRecipientUserId() const;
     User* getRecipient() const;
@@ -29,4 +30,7 @@ public:
     void setTitle(const std::string& title);
     void setMessage(const std::string& message);
     void setCreatedAt(const util::Timestamp& createdAt);
+    std::string serialize() const;
+    static Notification* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.cpp

@@ -1,4 +1,8 @@
+#include <sstream>
 #include "Service.h"
+#include "InventoryItem.h"
+#include "StringHelper.h"
+#include "Factory.h"
 
 int Service::m_uid = 0;
 
@@ -12,7 +16,42 @@ Service::Service(const std::string& name, const util::Map<std::string, Inventory
     m_name(name),
     m_requiredInventoryItems(requiredInventoryItems),
     m_status(util::State::ACTIVE),
-    m_laborCost(laborCost) {}
+    m_laborCost(laborCost) 
+{
+    int numberOfInventoryItems = m_requiredInventoryItems.getSize();
+    auto inventoryItemPointers = m_requiredInventoryItems.getValues();
+    for (int index = 0; index < numberOfInventoryItems; index++)
+    {
+        m_requiredInventoryItemIDs.push_back(inventoryItemPointers[index]->getId());
+    }
+}
+
+/*
+Function: Service (parameterized constructor with ID)
+Description: Initializes a service with an existing ID, name, inventory item IDs,
+             labor cost, and state. Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique service ID
+    - name: const std::string&, name of the service
+    - requiredInventoryItemIDs: const util::Vector<std::string>&, IDs of required inventory items
+    - laborCost: double, labor cost of the service
+    - status: util::State, state of the service (ACTIVE/INACTIVE)
+Returns:
+    - A new Service object
+*/
+Service::Service(const std::string& id, const std::string& name, const util::Vector<std::string>& requiredInventoryItemIDs, double laborCost, util::State status)
+    : m_id(id),
+    m_name(name),
+    m_requiredInventoryItemIDs(requiredInventoryItemIDs),
+    m_status(status),
+    m_laborCost(laborCost)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
 
 const std::string& Service::getId() const
 {
@@ -24,6 +63,19 @@ const std::string& Service::getName() const
     return m_name;
 }
 
+/*
+Function: getRequiredInventoryItemIDs
+Description: Retrieves the IDs of required inventory items for the service.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Inventory item IDs
+*/
+const util::Vector<std::string>& Service::getRequiredInventoryItemIDs() const
+{
+    return m_requiredInventoryItemIDs;
+}
+
 const util::Map<std::string, InventoryItem*>& Service::getRequiredInventoryItems() const
 {
     return m_requiredInventoryItems;
@@ -52,6 +104,13 @@ void Service::setName(const std::string& name)
 void Service::setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems)
 {
     m_requiredInventoryItems = requiredInventoryItems;
+    m_requiredInventoryItemIDs.clear();
+    int numberOfRequiredInventoryItems = m_requiredInventoryItems.getSize();
+    auto inventoryItemPointers = m_requiredInventoryItems.getValues();
+    for (int index = 0; index < numberOfRequiredInventoryItems; index++)
+    {
+        m_requiredInventoryItemIDs.push_back(inventoryItemPointers[index]->getId());
+    }
 }
 
 void Service::setLaborCost(double laborCost)
@@ -63,3 +122,118 @@ void Service::setState(util::State status)
 {
     m_status = status;
 }
+
+/*
+Function: getInventoryItemIDsAsString (static helper)
+Description: Converts a vector of inventory item IDs into a single string separated by '|'.
+Parameters:
+    - inventoryItemIds: const util::Vector<std::string>&, vector of inventory item IDs
+Returns:
+    - std::string: Concatenated inventory item IDs string
+*/
+static std::string getInventoryItemIDsAsString(const util::Vector<std::string>& inventoryItemIds)
+{
+    int numberOfInventoryItems = inventoryItemIds.getSize();
+    std::string inventoryItemIDs;
+    for (int index = 0; index < numberOfInventoryItems; index++)
+    {
+        inventoryItemIDs += inventoryItemIds[index];
+        if (index < numberOfInventoryItems - 1)
+        {
+            inventoryItemIDs += '|';
+        }
+    }
+    return inventoryItemIDs;
+}
+
+/*
+Function: getInventoryItemIDsAsVector (static helper)
+Description: Converts a string of inventory item IDs separated by '|' into a vector.
+Parameters:
+    - inventoryItemIDsString: const std::string&, concatenated inventory item IDs string
+Returns:
+    - util::Vector<std::string>: Vector of inventory item IDs
+*/
+static util::Vector<std::string> getInventoryItemIDsAsVector(const std::string& inventoryItemIDsString)
+{
+    util::Vector<std::string> inventoryItemIDs;
+    std::string inventoryItemID;
+    std::istringstream serializedInventoryItemIDs(inventoryItemIDsString);
+    while (getline(serializedInventoryItemIDs, inventoryItemID, '|'))
+    {
+        inventoryItemIDs.push_back(inventoryItemID);
+    }
+    return inventoryItemIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the service into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized service record
+*/
+std::string Service::serialize() const
+{
+    std::ostringstream serializedService;
+    serializedService << m_id << ','
+        << m_name << ','
+        << getInventoryItemIDsAsString(m_requiredInventoryItemIDs) << ','
+        << m_laborCost << ','
+        << util::getStateString(m_status);
+    return serializedService.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a Service object.
+Parameters:
+    - record: const std::string&, serialized service record
+Returns:
+    - Service*: Pointer to the deserialized Service object
+Throws:
+    - std::runtime_error if labor cost parsing fails
+*/
+Service* Service::deserialize(const std::string& record)
+{
+    std::string id, name;
+    std::string inventoryItemIDsString, laborCostString, statusString;
+    double laborCost;
+    std::istringstream serializedService(record);
+    getline(serializedService, id, ',');
+    getline(serializedService, name, ',');
+    getline(serializedService, inventoryItemIDsString, ',');
+    getline(serializedService, laborCostString, ',');
+    getline(serializedService, statusString, ',');
+    util::Vector<std::string> inventoryItemIDs = getInventoryItemIDsAsVector(inventoryItemIDsString);
+    try
+    {
+        laborCost = std::stod(laborCostString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid labor cost");
+    }
+    util::State status = util::getState(statusString);
+    return Factory::getObject<Service>(
+        id,
+        name,
+        inventoryItemIDs,
+        laborCost,
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Name,InventoryIDs,LaborCost,Status")
+*/
+std::string Service::getHeaders()
+{
+    return "ID,Name,InventoryIDs,LaborCost,Status";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class InventoryItem;
@@ -11,14 +12,17 @@ private:
     static int m_uid;
     std::string m_id;
     std::string m_name;
+    util::Vector<std::string> m_requiredInventoryItemIDs;
     util::Map<std::string, InventoryItem*> m_requiredInventoryItems;
     double m_laborCost;
     util::State m_status;
 public:
     Service();
     Service(const std::string& name, const util::Map<std::string, InventoryItem*>& requiredInventoryItems, double laborCost);
+    Service(const std::string& id, const std::string& name, const util::Vector<std::string>& requiredInventoryItemIDs, double laborCost, util::State state);
     const std::string& getId() const;
     const std::string& getName() const;
+    const util::Vector<std::string>& getRequiredInventoryItemIDs() const;
     const util::Map<std::string, InventoryItem*>& getRequiredInventoryItems() const;
     double getLaborCost() const;
     util::State getState() const;
@@ -27,4 +31,7 @@ public:
     void setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems);
     void setLaborCost(double laborCost);
     void setState(util::State status);
+    std::string serialize() const;
+    static Service* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.cpp

@@ -1,14 +1,20 @@
+#include <stdexcept>
+#include <sstream>
 #include "ServiceBooking.h"
+#include "Service.h"
+#include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int ServiceBooking::m_uid = 0;
 
 ServiceBooking::ServiceBooking()
     : m_id("SRV" + std::to_string(++m_uid)),
     m_customer(nullptr),
+    m_assignedTechnician(nullptr),
     m_discountPercentage(0.0) {}
 
 ServiceBooking::ServiceBooking(
-    const std::string& id,
     util::ServiceJobStatus status,
     const util::Map<std::string,
     Service*>& services,
@@ -18,7 +24,7 @@ ServiceBooking::ServiceBooking(
     const std::string& vehicleBrand,
     const std::string& vehicleModel,
     const std::string& assignedTechnicianId,
-    const User* assignedTechnician,
+    User* assignedTechnician,
     double discountPercentage
 )
     : m_id("SRV" + std::to_string(++m_uid)),
@@ -33,6 +39,60 @@ ServiceBooking::ServiceBooking(
     m_assignedTechnician(assignedTechnician),
     m_discountPercentage(discountPercentage)
 {
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
+}
+
+/*
+Function: ServiceBooking (parameterized constructor with ID)
+Description: Initializes a service booking with an existing ID, status, service IDs,
+             customer details, vehicle details, technician ID, and discount percentage.
+             Updates UID tracking based on ID.
+Parameters:
+    - id: const std::string&, unique booking ID
+    - status: util::ServiceJobStatus, job status of the booking
+    - serviceIDs: const util::Vector<std::string>&, IDs of booked services
+    - customerId: const std::string&, ID of the customer
+    - vehicleNumber: const std::string&, vehicle number
+    - vehicleBrand: const std::string&, vehicle brand
+    - vehicleModel: const std::string&, vehicle model
+    - assignedTechnicianId: const std::string&, ID of the assigned technician
+    - discountPercentage: double, discount applied
+Returns:
+    - A new ServiceBooking object
+*/
+ServiceBooking::ServiceBooking(
+    const std::string& id,
+    util::ServiceJobStatus status,
+    const util::Vector<std::string>& serviceIDs,
+    const std::string& customerId,
+    const std::string& vehicleNumber,
+    const std::string& vehicleBrand,
+    const std::string& vehicleModel,
+    const std::string& assignedTechnicianId,
+    double discountPercentage
+)
+    : m_id(id),
+    m_status(status),
+    m_serviceIDs(serviceIDs),
+    m_customerId(customerId),
+    m_customer(nullptr),
+    m_vehicleNumber(vehicleNumber),
+    m_vehicleBrand(vehicleBrand),
+    m_vehicleModel(vehicleModel),
+    m_assignedTechnicianId(assignedTechnicianId),
+    m_assignedTechnician(nullptr),
+    m_discountPercentage(discountPercentage)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
 }
 
 const std::string& ServiceBooking::getId() const
@@ -45,6 +105,19 @@ util::ServiceJobStatus ServiceBooking::getStatus() const
     return m_status;
 }
 
+/*
+Function: getServiceIDs
+Description: Retrieves the IDs of services booked.
+Parameters:
+    - None
+Returns:
+    - const util::Vector<std::string>&: Service IDs
+*/
+const util::Vector<std::string>& ServiceBooking::getServiceIDs() const
+{
+    return m_serviceIDs;
+}
+
 const util::Map<std::string, Service*>& ServiceBooking::getServices() const
 {
     return m_services;
@@ -103,6 +176,13 @@ void ServiceBooking::setStatus(const util::ServiceJobStatus& status)
 void ServiceBooking::setServices(const util::Map<std::string, Service*>& services)
 {
     m_services = services;
+    m_serviceIDs.clear();
+    int numberOfServices = m_services.getSize();
+    auto servicePointers = m_services.getValues();
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        m_serviceIDs.push_back(servicePointers[index]->getId());
+    }
 }
 
 void ServiceBooking::setCustomerId(const std::string& customerId)
@@ -135,7 +215,7 @@ void ServiceBooking::setAssignedTechnicianId(const std::string& assignedTechnici
     m_assignedTechnicianId = assignedTechnicianId;
 }
 
-void ServiceBooking::setAssignedTechnician(const User* assignedTechnician)
+void ServiceBooking::setAssignedTechnician(User* assignedTechnician)
 {
     m_assignedTechnician = assignedTechnician;
 }
@@ -144,3 +224,130 @@ void ServiceBooking::setDiscountPercentage(double discountPercentage)
 {
     m_discountPercentage = discountPercentage;
 }
+
+/*
+Function: getServiceIDsAsString (static helper)
+Description: Converts a vector of service IDs into a single string separated by '|'.
+Parameters:
+    - serviceIDs: const util::Vector<std::string>&, vector of service IDs
+Returns:
+    - std::string: Concatenated service IDs string
+*/
+static std::string getServiceIDsAsString(const util::Vector<std::string>& serviceIDs)
+{
+    int numberOfServices = serviceIDs.getSize();
+    std::string serviceIDsString;
+    for (int index = 0; index < numberOfServices; index++)
+    {
+        serviceIDsString += serviceIDs[index];
+        if (index < numberOfServices - 1)
+        {
+            serviceIDsString += '|';
+        }
+    }
+    return serviceIDsString;
+}
+
+/*
+Function: getServiceIDsAsVector (static helper)
+Description: Converts a string of service IDs separated by '|' into a vector.
+Parameters:
+    - serviceIDsString: const std::string&, concatenated service IDs string
+Returns:
+    - util::Vector<std::string>: Vector of service IDs
+*/
+static util::Vector<std::string> getServiceIDsAsVector(const std::string& serviceIDsString)
+{
+    util::Vector<std::string> serviceIDs;
+    std::string serviceID;
+    std::istringstream serializedServiceIDs(serviceIDsString);
+    while (getline(serializedServiceIDs, serviceID, '|'))
+    {
+        serviceIDs.push_back(serviceID);
+    }
+    return serviceIDs;
+}
+
+/*
+Function: serialize
+Description: Serializes the service booking into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized booking record
+*/
+std::string ServiceBooking::serialize() const
+{
+    std::ostringstream serializedBooking;
+    serializedBooking << m_id << ','
+        << util::getServiceJobStatusString(m_status) << ','
+        << getServiceIDsAsString(m_serviceIDs) << ','
+        << m_customerId << ','
+        << m_vehicleNumber << ','
+        << m_vehicleBrand << ','
+        << m_vehicleModel << ','
+        << m_assignedTechnicianId << ','
+        << m_discountPercentage << ',';
+    return serializedBooking.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a ServiceBooking object.
+Parameters:
+    - record: const std::string&, serialized booking record
+Returns:
+    - ServiceBooking*: Pointer to the deserialized ServiceBooking object
+Throws:
+    - std::runtime_error if discount percentage parsing fails
+*/
+ServiceBooking* ServiceBooking::deserialize(const std::string& record)
+{
+    std::string id, customerId, vehicleNumber, vehicleBrand, vehicleModel, assignedTechnicianId;
+    std::string serviceJobStatusString, serviceIDsString, discountPercentageString;
+    double discountPercentage;
+    std::istringstream serializedBooking(record);
+    getline(serializedBooking, id, ',');
+    getline(serializedBooking, serviceJobStatusString, ',');
+    getline(serializedBooking, serviceIDsString, ',');
+    getline(serializedBooking, customerId, ',');
+    getline(serializedBooking, vehicleNumber, ',');
+    getline(serializedBooking, vehicleBrand, ',');
+    getline(serializedBooking, vehicleModel, ',');
+    getline(serializedBooking, assignedTechnicianId, ',');
+    getline(serializedBooking, discountPercentageString, ',');
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid discount percentage");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(serviceJobStatusString);
+    return Factory::getObject<ServiceBooking>(
+        id,
+        status,
+        serviceIDs,
+        customerId,
+        vehicleNumber,
+        vehicleBrand,
+        vehicleModel,
+        assignedTechnicianId,
+        discountPercentage
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service booking serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage")
+*/
+std::string ServiceBooking::getHeaders()
+{
+    return "ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "Enums.h"
 
 class Service;
@@ -12,6 +13,7 @@ private:
     static int m_uid;
     std::string m_id;
     util::ServiceJobStatus m_status;
+    util::Vector<std::string> m_serviceIDs;
     util::Map<std::string, Service*> m_services;
     std::string m_customerId;
     User* m_customer;
@@ -19,12 +21,11 @@ private:
     std::string m_vehicleBrand;
     std::string m_vehicleModel;
     std::string m_assignedTechnicianId;
-    const User* m_assignedTechnician;
+    User* m_assignedTechnician;
     double m_discountPercentage;
 public:
     ServiceBooking();
     ServiceBooking(
-        const std::string& id,
         util::ServiceJobStatus status,
         const util::Map<std::string,
         Service*>& services,
@@ -34,11 +35,23 @@ public:
         const std::string& vehicleBrand,
         const std::string& vehicleModel,
         const std::string& assignedTechnicianId,
-        const User* assignedTechnician,
+        User* assignedTechnician,
+        double discountPercentage
+    );
+    ServiceBooking(
+        const std::string& id,
+        util::ServiceJobStatus status,
+        const util::Vector<std::string>& serviceIDs,
+        const std::string& customerId,
+        const std::string& vehicleNumber,
+        const std::string& vehicleBrand,
+        const std::string& vehicleModel,
+        const std::string& assignedTechnicianId,
         double discountPercentage
     );
     const std::string& getId() const;
     util::ServiceJobStatus getStatus() const;
+    const util::Vector<std::string>& getServiceIDs() const;
     const util::Map<std::string, Service*>& getServices() const;
     const std::string& getCustomerId() const;
     User* getCustomer() const;
@@ -57,6 +70,9 @@ public:
     void setVehicleBrand(const std::string& vehicleBrand);
     void setVehicleModel(const std::string& vehicleModel);
     void setAssignedTechnicianId(const std::string& assignedTechnicianId);
-    void setAssignedTechnician(const User* assignedTechnician);
+    void setAssignedTechnician(User* assignedTechnician);
     void setDiscountPercentage(double discountPercentage);
+    std::string serialize() const;
+    static ServiceBooking* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.cpp

@@ -1,6 +1,9 @@
+#include <sstream>
 #include "User.h"
 #include "Notification.h"
 #include "Enums.h"
+#include "Factory.h"
+#include "StringHelper.h"
 
 int User::m_uid = 0;
 
@@ -19,11 +22,45 @@ User::User(const std::string& userName, const std::string& password, const std::
     m_type(role),
     m_status(util::State::ACTIVE) {}
 
+/*
+Function: User (parameterized constructor with ID)
+Description: Initializes a user with an existing ID, credentials, personal details,
+             role, and state. Updates UID tracking based on ID.
+Parameters:
+    - userId: const std::string&, unique user ID
+    - userName: const std::string&, username
+    - password: const std::string&, password
+    - name: const std::string&, full name
+    - phone: const std::string&, phone number
+    - email: const std::string&, email address
+    - role: util::UserType, role of the user
+    - status: util::State, state of the user (ACTIVE/INACTIVE)
+Returns:
+    - A new User object
+*/
+User::User(const std::string& userId, const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role, util::State status)
+    : m_id(userId),
+    m_userName(userName),
+    m_password(password),
+    m_name(name),
+    m_phone(phone),
+    m_email(email),
+    m_type(role),
+    m_status(status)
+{
+    int idNumber = util::extractNumber(m_id);
+    if (idNumber > m_uid)
+    {
+        m_uid = idNumber;
+    }
+}
+
 User::~User()
 {
-    for (int index = 0; index < m_notifications.getSize(); index++)
+    auto values = m_notifications.getValues();
+    for (int index = 0; index < values.getSize(); index++)
     {
-        delete m_notifications.getValues()[index];
+        delete values[index];
     }
 }
 
@@ -120,3 +157,71 @@ void User::setState(util::State status)
 void User::update(Notification* notification)
 {
 }
+
+/*
+Function: serialize
+Description: Serializes the user into a CSV-formatted string.
+Parameters:
+    - None
+Returns:
+    - std::string: Serialized user record
+*/
+std::string User::serialize() const
+{
+    std::ostringstream serializedUser;
+    serializedUser << m_id << ','
+        << m_userName << ','
+        << m_password << ','
+        << m_name << ','
+        << m_phone << ','
+        << m_email << ','
+        << util::getUserTypeString(m_type) << ','
+        << util::getStateString(m_status);
+    return serializedUser.str();
+}
+
+/*
+Function: deserialize
+Description: Deserializes a CSV-formatted string into a User object.
+Parameters:
+    - record: const std::string&, serialized user record
+Returns:
+    - User*: Pointer to the deserialized User object
+*/
+User* User::deserialize(const std::string& record)
+{
+    std::string id, name, username, phone, password, email;
+    std::string userTypeString, stateString;
+    std::istringstream serializedUser(record);
+    getline(serializedUser, id, ',');
+    getline(serializedUser, username, ',');
+    getline(serializedUser, password, ',');
+    getline(serializedUser, name, ',');
+    getline(serializedUser, phone, ',');
+    getline(serializedUser, email, ',');
+    getline(serializedUser, userTypeString, ',');
+    getline(serializedUser, stateString);
+    util::UserType userType = util::getUserType(userTypeString);
+    util::State status = util::getState(stateString);
+    return Factory::getObject<User>(id,
+        username,
+        password,
+        name,
+        phone,
+        email,
+        userType,
+        status);
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for user serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Username,Password,Name,Phone,Email,UserType,UserStatus")
+*/
+std::string User::getHeaders()
+{
+    return "ID,Username,Password,Name,Phone,Email,UserType,UserStatus";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.h

@@ -22,6 +22,7 @@ private:
 public:
     User();
     User(const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role);
+    User(const std::string& userId, const std::string& userName, const std::string& password, const std::string& name, const std::string& phone, const std::string& email, util::UserType role, util::State status);
     ~User();
     const std::string& getId() const;
     const std::string& getUserName() const;
@@ -42,4 +43,7 @@ public:
     void setRole(util::UserType role);
     void setState(util::State status);
     void update(Notification* notification) override;
+    std::string serialize() const;
+    static User* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp

@@ -1 +1,104 @@
+/*
+File: InventoryManagementService.cpp
+Description: Implements the InventoryManagementService class, which manages inventory
+			 items and observer relationships within the system. Provides methods
+			 for loading and saving inventory items from persistent storage, as well
+			 as attaching and persisting observers for notification handling.
+Author: Trenser
+Date: 22-May-2026
+*/
+
 #include "InventoryManagementService.h"
+#include "FileManager.h"
+#include "InventoryItem.h"
+#include "Utility.h"
+#include "Config.h"
+
+/*
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+			 InventoryManagementService.
+Parameters:
+	- None
+Returns:
+	- util::Vector<std::string>: Vector of observer user IDs
+*/
+util::Vector<std::string> InventoryManagementService::getObserverIDs()
+{
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
+}
+
+/*
+Function: loadInventoryItems
+Description: Loads inventory items from persistent storage into the datastore.
+			 Uses FileManager to deserialize inventory items from the configured file.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::loadInventoryItems()
+{
+	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
+	auto& inventoryItems = m_dataStore.getInventoryItems();
+	auto inventoryItemsMap = inventoryItemFileManager.load();
+	int numberOfInventoryItems = inventoryItemsMap.getSize();
+	for (int index = 0; index < numberOfInventoryItems; index++)
+	{
+		inventoryItems[inventoryItemsMap.getKeyAt(index)] = inventoryItemsMap.getValueAt(index);
+	}
+}
+
+/*
+Function: saveInventoryItems
+Description: Saves inventory items from the datastore to persistent storage.
+			 Uses FileManager to serialize inventory items into the configured file.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::saveInventoryItems()
+{
+	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
+	auto& inventoryItems = m_dataStore.getInventoryItems();
+	inventoryItemFileManager.save(inventoryItems);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+			 users as observers to the InventoryManagementService.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::loadObservers()
+{
+	util::loadObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the InventoryManagementService
+			 to persistent storage for future retrieval.
+Parameters:
+	- None
+Returns:
+	- void
+*/
+void InventoryManagementService::saveObservers()
+{
+	util::saveObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <string>
 #include "Map.h"
+#include "Vector.h"
 #include "NotificationManagementService.h"
 #include "DataStore.h"
 
@@ -11,6 +12,7 @@ class InventoryManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     InventoryManagementService() : m_dataStore(DataStore::getInstance()) {}
     util::Map<std::string, InventoryItem*> getInventoryItems();
@@ -21,4 +23,8 @@ public:
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
+    void loadInventoryItems();
+    void saveInventoryItems();
+    void loadObservers();
+    void saveObservers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/NotificationManagementService.h

@@ -10,4 +10,5 @@ public:
 	virtual void sendNotification(User* recipient, const std::string& title, const std::string& message) = 0;
 	virtual void attach(User* user) = 0;
 	virtual void detach(User* user) = 0;
+	virtual util::Vector<std::string> getObserverIDs() = 0;
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.cpp

@@ -1 +1,123 @@
+#include <stdexcept>
 #include "PaymentManagementService.h"
+#include "Invoice.h"
+#include "FileManager.h"
+#include "Utility.h"
+#include "Config.h"
+
+/*
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+             PaymentManagementService.
+Parameters:
+    - None
+Returns:
+    - util::Vector<std::string>: Vector of observer user IDs
+*/
+util::Vector<std::string> PaymentManagementService::getObserverIDs()
+{
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
+}
+
+/*
+Function: loadInvoices
+Description: Loads invoices from persistent storage into the datastore.
+             Validates associated service bookings and inventory parts before
+             attaching them to each invoice. Throws exceptions if invalid IDs
+             are encountered.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a booking ID or part ID is invalid
+*/
+void PaymentManagementService::loadInvoices()
+{
+    util::FileManager<Invoice> invoiceFileManager(config::file::INVOICE_FILE);
+    auto& invoices = m_dataStore.getInvoices();
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& inventoryItems = m_dataStore.getInventoryItems();
+    auto invoicesMap = invoiceFileManager.load();
+    for (int invoiceIndex = 0; invoiceIndex < invoicesMap.getSize(); invoiceIndex++)
+    {
+        Invoice* invoice = invoicesMap.getValueAt(invoiceIndex);
+        int bookingIndex = serviceBookings.find(invoice->getBookingId());
+        if (bookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid Booking ID");
+        }
+        ServiceBooking* booking = serviceBookings.getValueAt(bookingIndex);
+        invoice->setBooking(booking);
+        util::Map<std::string, InventoryItem*> invoiceParts;
+        auto& partIDs = invoice->getPartIDs();
+        for (int partIndex = 0; partIndex < partIDs.getSize(); partIndex++)
+        {
+            const std::string& partID = partIDs[partIndex];
+            int inventoryIndex = inventoryItems.find(partID);
+            if (inventoryIndex == -1)
+            {
+                throw std::runtime_error("Invalid Part ID");
+            }
+            invoiceParts[partID] = inventoryItems.getValueAt(inventoryIndex);
+        }
+        invoice->setParts(invoiceParts);
+        invoices[invoice->getId()] = invoice;
+    }
+}
+
+/*
+Function: saveInvoices
+Description: Saves invoices from the datastore to persistent storage.
+             Uses FileManager to serialize invoices into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void PaymentManagementService::saveInvoices()
+{
+    util::FileManager<Invoice> invoiceFileManager(config::file::INVOICE_FILE);
+    auto& invoices = m_dataStore.getInvoices();
+    invoiceFileManager.save(invoices);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+             users as observers to the PaymentManagementService.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if an observer ID is invalid (not found in datastore)
+*/
+void PaymentManagementService::loadObservers()
+{
+    util::loadObservers(config::file::PAYMENTMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the PaymentManagementService
+             to persistent storage for future retrieval.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void PaymentManagementService::saveObservers()
+{
+    util::saveObservers(config::file::PAYMENTMANAGEMENTOBSERVERS, this);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/PaymentManagementService.h

@@ -13,6 +13,7 @@ class PaymentManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     PaymentManagementService() : m_dataStore(DataStore::getInstance()) {}
     void generateInvoice(ServiceBooking* booking);
@@ -22,4 +23,8 @@ public:
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
+    void loadInvoices();
+    void saveInvoices();
+    void loadObservers();
+    void saveObservers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.cpp

@@ -1,324 +1,326 @@
+#include <stdexcept>
 #include "ServiceManagementService.h"
-#include "UserManagementService.h"
-#include "ServiceBooking.h"
-#include "Factory.h"
-#include "JobCard.h"
-#include "Timestamp.h"
+#include "FileManager.h"
 #include "Service.h"
-#include "Enums.h"
-#include "InventoryItem.h"
-#include "AuthenticationManagementService.h"
-#include "PaymentManagementService.h"
-#include "NotificationManagementService.h"
-#include "User.h"
+#include "ComboPackage.h"
+#include "ServiceBooking.h"
+#include "JobCard.h"
+#include "Config.h"
+#include "Utility.h"
 
 /*
-Function: getServiceBookings
-Description: Retrieves all service bookings from the datastore.
+Function: getObserverIDs
+Description: Retrieves the IDs of all observers currently attached to the
+             ServiceManagementService.
 Parameters:
     - None
 Returns:
-	- util::Map<std::string, ServiceBooking*> containing all service bookings
+    - util::Vector<std::string>: Vector of observer user IDs
 */
-util::Map<std::string, ServiceBooking*> ServiceManagementService::getServiceBookings()
+util::Vector<std::string> ServiceManagementService::getObserverIDs()
 {
-	return m_dataStore.getServiceBookings();
+	util::Vector<std::string> observerIDs;
+	int numberOfObservers = m_observers.getSize();
+	for (int index = 0; index < numberOfObservers; index++)
+	{
+		User* observer = m_observers.getValueAt(index);
+		if (observer)
+		{
+			observerIDs.push_back(observer->getId());
+		}
+	}
+	return observerIDs;
 }
 
 /*
-Function: getServiceBooking
-Description: Retrieves a specific service booking by its ID.
-Parameters:
-	- serviceID: std::string, ID of the service booking
-Returns:
-	- ServiceBooking*: Pointer to the service booking, or nullptr if not found
-*/
-ServiceBooking* ServiceManagementService::getServiceBooking(const std::string& serviceID)
-{
-	auto currentServiceBookings = getServiceBookings();
-	for (int iterator = 0; iterator < currentServiceBookings.getSize(); iterator++)
-	{
-		if (currentServiceBookings.getValueAt(iterator)->getId() == serviceID)
-		{
-			return currentServiceBookings.getValueAt(iterator);
-		}
-	}
-	return nullptr;
-}
-
-/*
-Function: createJobCard
-Description: Creates a job card for a given service booking, service, and technician.
-			 Validates booking, service, technician, and inventory availability before creation.
-Parameters:
-	- bookingID: std::string, ID of the service booking
-	- technicianID: std::string, ID of the technician
-	- serviceID: std::string, ID of the service
-Returns:
-	- void
-Throws:
-	- std::runtime_error if booking, service, technician, or inventory validation fails
-*/
-void ServiceManagementService::createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID)
-{
-	UserManagementService m_userManagementService;
-	ServiceBooking* currentBooking = getServiceBooking(bookingID);
-	auto& currentJobCards = m_dataStore.getJobCards();
-	if (currentBooking == nullptr)
-	{
-		throw std::runtime_error("Service Booking not available");
-	}
-	auto& currentServices = currentBooking->getServices();
-	if (currentServices.find(serviceID) == -1)
-	{
-		throw std::runtime_error("Invalid service Id");
-	}
-	Service* currentService = currentServices.getValueAt(currentServices.find(serviceID));
-	User* selectedTechnician = m_userManagementService.getUser(technicianID);
-	if (selectedTechnician == nullptr)
-	{
-		throw std::runtime_error("Technician not available");
-	}
-	auto& inventoryItems = currentService->getRequiredInventoryItems();
-	for (int iterator = 0; iterator < inventoryItems.getSize(); iterator++)
-	{
-		InventoryItem* currentInventoryItem = inventoryItems.getValueAt(iterator);
-		if (currentInventoryItem->getQuantity() == 0)
-		{
-			std::string errorMessage = "Failed to create job card, " + currentInventoryItem->getPartName() + " is out of stock.";
-			throw std::runtime_error(errorMessage);
-		}
-		else
-		{
-			int currentStockQuantity = currentInventoryItem->getQuantity();
-			currentInventoryItem->setQuantity(currentStockQuantity - 1);
-		}
-	}
-	currentBooking->setAssignedTechnician(selectedTechnician);
-	currentBooking->setAssignedTechnicianId(selectedTechnician->getId());
-	std::string title = "Job card created";
-	std::string message = "Job card created for the service and you are assigned for that.";
-	JobCard* jobCard = Factory::getObject<JobCard>(bookingID, currentBooking, currentService, serviceID, technicianID, selectedTechnician, util::Timestamp(), util::ServiceJobStatus::STARTED, util::Timestamp());
-	currentJobCards.insert(jobCard->getId(), jobCard);
-	sendNotification(selectedTechnician,title, message);
-}
-
-/*
-Function: createService
-Description: Creates a new service with associated inventory items and labor cost.
-			 Validates inventory items before creation.
-Parameters:
-	- name: std::string, name of the service
-	- inventoryItemIDs: util::Vector<std::string>, IDs of required inventory items
-	- laborCost: double, labor cost for the service
-Returns:
-	- void
-Throws:
-	- std::runtime_error if inventory items are not found or service creation fails
-*/
-void ServiceManagementService::createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost)
-{
-	util::Map<std::string, InventoryItem*> currentServiceInventoryItems;
-	auto inventoryItems = m_dataStore.getInventoryItems();
-	for (int iteratorOne =0; iteratorOne < inventoryItemIDs.getSize(); iteratorOne++)
-	{
-		std::string currentItemID = inventoryItemIDs[iteratorOne];
-		bool itemFound = false;
-		for (int iteratorTwo = 0; iteratorTwo < inventoryItems.getSize(); iteratorTwo++)
-		{
-			InventoryItem* currentInventoryItem = inventoryItems.getValueAt(iteratorTwo);
-			if (currentInventoryItem && currentInventoryItem->getId() == currentItemID)
-			{
-				itemFound = true;
-				currentServiceInventoryItems.insert(currentInventoryItem->getId(), currentInventoryItem);
-				break;
-			}
-		}
-		if (!itemFound)
-		{
-			throw std::runtime_error("Inventory item with ID '" + currentItemID + "' not found.");
-		}
-	}
-	Service* newService = Factory::getObject<Service>(name, currentServiceInventoryItems, laborCost);
-	if (newService == nullptr)
-	{
-		throw std::runtime_error("Unable to create new service.");
-	}
-	util::Map<std::string, Service*>& currentServices = m_dataStore.getServices();
-	if (currentServices.find(newService->getId()) != -1)
-	{
-		throw std::runtime_error("Service with this ID Already exists.");
-	}
-	currentServices.insert(newService->getId(), newService);
-}
-
-/*
-Function: getServices
-Description: Retrieves all services from the datastore.
+Function: loadServices
+Description: Loads services from persistent storage into the datastore.
+             Validates required inventory items and attaches them to each service.
 Parameters:
     - None
 Returns:
-	- util::Map<std::string, Service*> containing all services
+    - void
+Throws:
+    - std::runtime_error if an inventory item ID is invalid
 */
-util::Map<std::string, Service*> ServiceManagementService::getServices()
+void ServiceManagementService::loadServices()
 {
-	return m_dataStore.getServices();
+    util::FileManager<Service> serviceFileManager(config::file::SERVICE_FILE);
+    auto& services = m_dataStore.getServices();
+    auto& inventoryItems = m_dataStore.getInventoryItems();
+    auto servicesMap = serviceFileManager.load();
+    for (int serviceIndex = 0; serviceIndex < servicesMap.getSize(); serviceIndex++)
+    {
+        Service* service = servicesMap.getValueAt(serviceIndex);
+        services[service->getId()] = service;
+        util::Map<std::string, InventoryItem*> inventoryItemsMap;
+        auto& inventoryItemIDs = service->getRequiredInventoryItemIDs();
+        for (int inventoryItemIndex = 0; inventoryItemIndex < inventoryItemIDs.getSize(); inventoryItemIndex++)
+        {
+            const std::string& inventoryItemID = inventoryItemIDs[inventoryItemIndex];
+            int index = inventoryItems.find(inventoryItemID);
+            if (index == -1)
+            {
+                throw std::runtime_error("Invalid Inventory Item ID");
+            }
+            inventoryItemsMap[inventoryItemID] = inventoryItems.getValueAt(index);
+        }
+        service->setRequiredInventoryItems(inventoryItemsMap);
+    }
 }
 
 /*
-Function: removeService
-Description: Marks a service as inactive by its ID.
+Function: saveServices
+Description: Saves services from the datastore to persistent storage.
+             Uses FileManager to serialize services into the configured file.
 Parameters:
-	- serviceID: std::string, ID of the service
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveServices()
+{
+	util::FileManager<Service> serviceFileManager(config::file::SERVICE_FILE);
+	auto& services = m_dataStore.getServices();
+	serviceFileManager.save(services);
+}
+
+/*
+Function: loadComboPackages
+Description: Loads combo packages from persistent storage into the datastore.
+             Validates associated services and attaches them to each package.
+Parameters:
+    - None
 Returns:
     - void
 Throws:
-	- std::runtime_error if the service is not found
+    - std::runtime_error if a service ID is invalid
 */
-void ServiceManagementService::removeService(const std::string& serviceID)
+void ServiceManagementService::loadComboPackages()
 {
-	util::Map<std::string, Service*> currentServices = getServices();
-	if (currentServices.find(serviceID) != -1)
+    util::FileManager<ComboPackage> comboPackageFileManager(config::file::COMBOPACKAGE_FILE);
+    auto& comboPackages = m_dataStore.getComboPackages();
+    auto& services = m_dataStore.getServices();
+    auto comboPackagesMap = comboPackageFileManager.load();
+    for (int packageIndex = 0; packageIndex < comboPackagesMap.getSize(); packageIndex++)
     {
-		currentServices.getValueAt(currentServices.find(serviceID))->setState(util::State::INACTIVE);
+        ComboPackage* comboPackage = comboPackagesMap.getValueAt(packageIndex);
+        util::Map<std::string, Service*> packageServices;
+        auto& serviceIDs = comboPackage->getServiceIDs();
+        for (int serviceIndex = 0; serviceIndex < serviceIDs.getSize(); serviceIndex++)
+        {
+            const std::string& serviceID = serviceIDs[serviceIndex];
+            int serviceMapIndex = services.find(serviceID);
+            if (serviceMapIndex == -1)
+            {
+                throw std::runtime_error("Invalid Service ID");
             }
-	else
-	{
-		throw std::runtime_error("Service not found.");
+            packageServices[serviceID] = services.getValueAt(serviceMapIndex);
+        }
+        comboPackage->setServices(packageServices);
+        comboPackages[comboPackage->getId()] = comboPackage;
     }
 }
 
 /*
-Function: getServiceBookings (overloaded)
-Description: Retrieves all service bookings for a specific customer.
+Function: saveComboPackages
+Description: Saves combo packages from the datastore to persistent storage.
+             Uses FileManager to serialize combo packages into the configured file.
 Parameters:
-	- customerID: std::string, ID of the customer
+    - None
 Returns:
-	- util::Map<std::string, ServiceBooking*> containing bookings for the customer
+    - void
 */
-util::Map<std::string, ServiceBooking*> ServiceManagementService::getServiceBookings(const std::string& customerID)
+void ServiceManagementService::saveComboPackages()
 {
-	util::Map<std::string, ServiceBooking*> currentServiceBookings = getServiceBookings();
-	util::Map<std::string, ServiceBooking*> currentUserServiceBookings;
-	if (currentServiceBookings.getSize() != 0)
-	{
-		for (int iterator = 0; iterator < currentServiceBookings.getSize(); iterator++)
-		{
-			auto currentServiceBooking = currentServiceBookings.getValueAt(iterator);
-			if (currentServiceBooking->getCustomerId() == customerID)
-			{
-				currentUserServiceBookings.insert(currentServiceBooking->getId(), currentServiceBooking);
-			}
-		}
-	}
-	return currentUserServiceBookings;
+    util::FileManager<ComboPackage> comboPackageFileManager(config::file::COMBOPACKAGE_FILE);
+    auto& comboPackages = m_dataStore.getComboPackages();
+    comboPackageFileManager.save(comboPackages);
 }
 
 /*
-Function: getJobCards
-Description: Retrieves all job cards assigned to a specific technician.
+Function: loadServiceBookings
+Description: Loads service bookings from persistent storage into the datastore.
+             Validates associated services, customers, and technicians before
+             attaching them to each booking.
 Parameters:
-	- technicianID: std::string, ID of the technician
-Returns:
-	- util::Map<std::string, JobCard*> containing job cards assigned to the technician
-*/
-util::Map<std::string, JobCard*> ServiceManagementService::getJobCards(const std::string& technicianID)
-{
-	util::Map<std::string, JobCard*> jobCards = m_dataStore.getJobCards();
-	util::Map<std::string, JobCard*> technicianJobCards;
-	for (int iterator = 0; iterator < jobCards.getSize(); iterator++)
-	{
-		JobCard* currentJobCard = jobCards.getValueAt(iterator);
-		if (currentJobCard->getTechnicianId() == technicianID)
-		{
-			technicianJobCards.insert(currentJobCard->getId(), currentJobCard);
-		}
-	}
-	return technicianJobCards;
-}
-
-/*
-Function: hasAllJobCardsinServiceBookingCompleted (static helper)
-Description: Checks if all job cards for a given service booking are completed.
-Parameters:
-	- bookingId: std::string, ID of the service booking
-	- currentAssignedJobs: util::Map<std::string, JobCard*>&, map of assigned job cards
-Returns:
-	- bool: True if all job cards are completed, False otherwise
-*/
-static bool hasAllJobCardsinServiceBookingCompleted(std::string bookingId, util::Map<std::string, JobCard*>& currentAssignedJobs)
-{
-	for (int iterator = 0; iterator < currentAssignedJobs.getSize(); iterator++)
-	{
-		JobCard* currentJob = currentAssignedJobs.getValueAt(iterator);
-		if (currentJob->getBookingId() == bookingId)
-		{
-			if (currentJob->getStatus() == util::ServiceJobStatus::STARTED)
-			{
-				return false;
-			}
-		}
-	}
-	return true;
-}
-
-/*
-Function: completeJob
-Description: Marks a job card as completed for the authenticated technician.
-			 If all job cards in the booking are completed, marks the booking as completed
-			 and generates an invoice.
-Parameters:
-	- jobID: std::string, ID of the job card
+    - None
 Returns:
     - void
 Throws:
-	- std::runtime_error if technician is not authenticated, job card not found, or job already completed
+    - std::runtime_error if a service ID, customer ID, or technician ID is invalid
+    - std::runtime_error if a user is not of the expected type (customer/technician)
 */
-void ServiceManagementService::completeJob(const std::string& jobID)
+void ServiceManagementService::loadServiceBookings()
 {
-	AuthenticationManagementService authenticationManagementService;
-	PaymentManagementService paymentManagementService;
-	bool jobStatusUpdated = false, serviceBookingCompleted;
-	JobCard* currentJob;
-	User* currentTechnician = authenticationManagementService.getAuthenticatedUser();
-	if (currentTechnician == nullptr)
+    util::FileManager<ServiceBooking> bookingFileManager(config::file::SERVICEBOOKING_FILE);
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& services = m_dataStore.getServices();
+    auto& users = m_dataStore.getUsers();
+    auto bookingsMap = bookingFileManager.load();
+    for (int bookingIndex = 0; bookingIndex < bookingsMap.getSize(); bookingIndex++)
     {
-		throw std::runtime_error("Unable to fetch current technician.");
-	}
-	util::Map<std::string, JobCard*> currentAssignedJobs = getJobCards(currentTechnician->getId());
-	if (currentAssignedJobs.getSize() == 0)
+        ServiceBooking* booking = bookingsMap.getValueAt(bookingIndex);
+        util::Map<std::string, Service*> bookingServices;
+        auto& serviceIDs = booking->getServiceIDs();
+        for (int serviceIndex = 0; serviceIndex < serviceIDs.getSize(); serviceIndex++)
         {
-		throw std::runtime_error("No job cards assigned to the technician.");
-	}
-	if (currentAssignedJobs.find(jobID) != -1)
+            const std::string& serviceID = serviceIDs[serviceIndex];
+            int serviceMapIndex = services.find(serviceID);
+            if (serviceMapIndex == -1)
             {
-		currentJob = currentAssignedJobs.getValueAt(currentAssignedJobs.find(jobID));
-		if (currentJob == nullptr)
-		{
-			throw std::runtime_error("Unable to fetch current job.");
-		}
-		if (currentJob->getStatus() == util::ServiceJobStatus::STARTED)
-		{
-			currentJob->setStatus(util::ServiceJobStatus::COMPLETED);
-			jobStatusUpdated = true;
-		}
-	}
-	else
-	{
-		throw std::runtime_error("Failed to complete the job, some error occured or job already completed.");
-	}
-	if (!jobStatusUpdated)
-	{
-		throw std::runtime_error("Failed to complete the job, some error occured or job already completed.");
+                throw std::runtime_error("Invalid Service ID");
             }
 
-	serviceBookingCompleted = hasAllJobCardsinServiceBookingCompleted(currentJob->getBookingId(), currentAssignedJobs);
-	if (serviceBookingCompleted)
+            bookingServices[serviceID] = services.getValueAt(serviceMapIndex);
+        }
+        booking->setServices(bookingServices);
+        int customerIndex = users.find(booking->getCustomerId());
+        if (customerIndex == -1)
         {
-		currentJob->getBooking()->setStatus(util::ServiceJobStatus::COMPLETED);
-		paymentManagementService.generateInvoice(currentJob->getBooking());
-		std::string title = "Service Booking completed,Invoice Generated.\n";
-		std::string message = "Services completed for the booking and invoice generated.\n";
-		sendNotification(currentJob->getBooking()->getCustomer(), title, message);
+            throw std::runtime_error("Invalid Customer ID");
+        }
+        User* customer = users.getValueAt(customerIndex);
+        if (customer->getUserType() != util::UserType::CUSTOMER)
+        {
+            throw std::runtime_error("User is not a customer");
+        }
+        booking->setCustomer(customer);
+        const std::string& technicianId = booking->getAssignedTechnicianId();
+        if (!technicianId.empty())
+        {
+            int technicianIndex = users.find(technicianId);
+            if (technicianIndex == -1)
+            {
+                throw std::runtime_error("Invalid Technician ID");
+            }
+            User* technician = users.getValueAt(technicianIndex);
+            if (technician->getUserType() != util::UserType::TECHNICIAN)
+            {
+                throw std::runtime_error("User is not a technician");
+            }
+            booking->setAssignedTechnician(technician);
+        }
+        serviceBookings[booking->getId()] = booking;
     }
 }
+
+/*
+Function: saveServiceBookings
+Description: Saves service bookings from the datastore to persistent storage.
+             Uses FileManager to serialize bookings into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveServiceBookings()
+{
+    util::FileManager<ServiceBooking> bookingFileManager(config::file::SERVICEBOOKING_FILE);
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    bookingFileManager.save(serviceBookings);
+}
+
+/*
+Function: loadJobCards
+Description: Loads job cards from persistent storage into the datastore.
+             Validates associated bookings, services, and technicians before
+             attaching them to each job card.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a booking ID, service ID, or technician ID is invalid
+    - std::runtime_error if a service does not belong to the booking
+    - std::runtime_error if a user is not a technician
+*/
+void ServiceManagementService::loadJobCards()
+{
+    util::FileManager<JobCard> jobCardFileManager(config::file::JOBCARD_FILE);
+    auto& jobCards = m_dataStore.getJobCards();
+    auto& serviceBookings = m_dataStore.getServiceBookings();
+    auto& services = m_dataStore.getServices();
+    auto& users = m_dataStore.getUsers();
+    auto jobCardsMap = jobCardFileManager.load();
+    for (int jobCardIndex = 0; jobCardIndex < jobCardsMap.getSize(); jobCardIndex++)
+    {
+        JobCard* jobCard = jobCardsMap.getValueAt(jobCardIndex);
+        int bookingIndex = serviceBookings.find(jobCard->getBookingId());
+        if (bookingIndex == -1)
+        {
+            throw std::runtime_error("Invalid Booking ID");
+        }
+        ServiceBooking* booking = serviceBookings.getValueAt(bookingIndex);
+        jobCard->setBooking(booking);
+        int serviceIndex = services.find(jobCard->getServiceId());
+        if (serviceIndex == -1)
+        {
+            throw std::runtime_error("Invalid Service ID");
+        }
+        Service* service = services.getValueAt(serviceIndex);
+        if (booking->getServices().find(jobCard->getServiceId()) == -1)
+        {
+            throw std::runtime_error("Service does not belong to booking");
+        }
+        jobCard->setService(service);
+        int technicianIndex = users.find(jobCard->getTechnicianId());
+        if (technicianIndex == -1)
+        {
+            throw std::runtime_error("Invalid Technician ID");
+        }
+        User* technician = users.getValueAt(technicianIndex);
+        if (technician->getUserType() != util::UserType::TECHNICIAN)
+        {
+            throw std::runtime_error("User is not a technician");
+        }
+        jobCard->setTechnician(technician);
+        jobCards[jobCard->getId()] = jobCard;
+    }
+}
+
+/*
+Function: saveJobCards
+Description: Saves job cards from the datastore to persistent storage.
+             Uses FileManager to serialize job cards into the configured file.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveJobCards()
+{
+    util::FileManager<JobCard> jobCardFileManager(config::file::JOBCARD_FILE);
+    auto& jobCards = m_dataStore.getJobCards();
+    jobCardFileManager.save(jobCards);
+}
+
+/*
+Function: loadObservers
+Description: Loads observer IDs from persistent storage and attaches corresponding
+             users as observers to the ServiceManagementService.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if an observer ID is invalid (not found in datastore)
+*/
+void ServiceManagementService::loadObservers()
+{
+    util::loadObservers(config::file::SERVICEMANAGEMENTOBSERVERS, this, m_dataStore);
+}
+
+/*
+Function: saveObservers
+Description: Saves the current observer IDs of the ServiceManagementService
+             to persistent storage for future retrieval.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void ServiceManagementService::saveObservers()
+{
+    util::saveObservers(config::file::SERVICEMANAGEMENTOBSERVERS, this);
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/ServiceManagementService.h

@@ -14,6 +14,7 @@ class ServiceManagementService : public NotificationManagementService
 private:
     DataStore& m_dataStore;
     static util::Map<std::string, User*> m_observers;
+    util::Vector<std::string> getObserverIDs() override;
 public:
     ServiceManagementService() : m_dataStore(DataStore::getInstance()) {}
     util::Map<std::string, Service*> getServices();
@@ -22,7 +23,6 @@ public:
     void purchaseComboPackage(const std::string& comboPackageID, const std::string& vehicleNumber, const std::string& vehicleBrand, const std::string& vehicleModel);
     util::Map<std::string, ServiceBooking*> getServiceBookings();
     util::Map<std::string, ServiceBooking*> getServiceBookings(const std::string& customerID);
-    ServiceBooking* getServiceBooking(const std::string& serviceID);
     void createJobCard(const std::string& bookingID, const std::string& technicianID, const std::string& serviceID);
     void createService(const std::string& name, const util::Vector<std::string>& inventoryItemIDs, double laborCost);
     void removeService(const std::string& serviceID);
@@ -35,4 +35,14 @@ public:
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
+    void loadServices();
+    void saveServices();
+    void loadComboPackages();
+    void saveComboPackages();
+    void loadServiceBookings();
+    void saveServiceBookings();
+    void loadJobCards();
+    void saveJobCards();
+    void loadObservers();
+    void saveObservers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp

@@ -1,31 +1,73 @@
 #include "UserManagementService.h"
+#include "FileManager.h"
 #include "User.h"
+#include "Notification.h"
+#include "Config.h"
 
-util::Map<std::string, User*> UserManagementService::getUsers(util::UserType type)
+/*
+Function: loadUsers
+Description: Loads users and notifications from persistent storage into the datastore.
+             Validates that each notification’s recipient exists and attaches the
+             notification to the corresponding user.
+Parameters:
+    - None
+Returns:
+    - void
+Throws:
+    - std::runtime_error if a notification recipient user ID is invalid
+*/
+void UserManagementService::loadUsers()
 {
-	util::Map<std::string, User*>& currentUsers = m_dataStore.getUsers();
-	util::Map<std::string, User*> filteredUsersMap;
-	for (int iterator = 0; iterator < currentUsers.getSize(); iterator++)
+    util::FileManager<User> userFileManager(config::file::USER_FILE);
+    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
+    auto& users = m_dataStore.getUsers();
+    auto usersMap = userFileManager.load();
+    auto notificationsMap = notificationFileManager.load();
+    int numberOfUsers = usersMap.getSize();
+    int numberOfNotifications = notificationsMap.getSize();
+    for (int index = 0; index < numberOfUsers; index++)
     {
-		User* currentUser = currentUsers.getValueAt(iterator);
-		if (currentUser->getUserType() == type)
+        users[usersMap.getKeyAt(index)] = usersMap.getValueAt(index);
+    }
+    for (int index = 0; index < numberOfNotifications; index++)
     {
-			filteredUsersMap.insert(currentUser->getId(), currentUser);
+        Notification* notification = notificationsMap.getValueAt(index);
+        const std::string& recipientUserId = notification->getRecipientUserId();
+        int userIndex = users.find(recipientUserId);
+        if (userIndex == -1)
+        {
+            throw std::runtime_error("Invalid recipient user ID");
         }
+        User* user = users.getValueAt(userIndex);
+        user->addNotification(notification);
     }
-	return filteredUsersMap;
 }
 
-User* UserManagementService::getUser(const std::string& userID)
+/*
+Function: saveUsers
+Description: Saves users and their notifications from the datastore to persistent storage.
+             Collects notifications from all users into a single map before saving.
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void UserManagementService::saveUsers()
 {
-	util::Map<std::string, User*>& currentUsers = m_dataStore.getUsers();
-	for (int iterator = 0; iterator < currentUsers.getSize(); iterator++)
+    util::FileManager<User> userFileManager(config::file::USER_FILE);
+    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
+    auto& users = m_dataStore.getUsers();
+    util::Map<std::string, Notification*> notifications;
+    for (int userIndex = 0; userIndex < users.getSize(); userIndex++)
     {
-		User* currentUser = currentUsers.getValueAt(iterator);
-		if (currentUser->getId() == userID)
+        User* user = users.getValueAt(userIndex);
+        auto& userNotifications = user->getNotifications();
+        for (int notificationIndex = 0; notificationIndex < userNotifications.getSize(); notificationIndex++)
         {
-			return currentUser;
+            notifications[userNotifications.getKeyAt(notificationIndex)] =
+                userNotifications.getValueAt(notificationIndex);
         }
     }
-	return nullptr;
+    userFileManager.save(users);
+    notificationFileManager.save(notifications);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.h

@@ -21,4 +21,6 @@ public:
     void removeUser(const std::string& userID);
     util::Vector<Notification*> getUserNotifications(const std::string& userID);
     void deleteNotification(const std::string& notificationID, const std::string& userID);
+    void loadUsers();
+    void saveUsers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Config.h

@@ -0,0 +1,19 @@
+#pragma once
+
+namespace config
+{
+	namespace file
+	{
+		constexpr const char* INVENTORYITEM_FILE = "files/InventoryItem.csv";
+		constexpr const char* USER_FILE = "files/User.csv";
+		constexpr const char* NOTIFICATION_FILE = "files/Notification.csv";
+		constexpr const char* SERVICE_FILE = "files/Service.csv";
+		constexpr const char* COMBOPACKAGE_FILE = "files/ComboPackage.csv";
+		constexpr const char* SERVICEBOOKING_FILE = "files/ServiceBooking.csv";
+		constexpr const char* JOBCARD_FILE = "files/JobCard.csv";
+		constexpr const char* INVOICE_FILE = "files/Invoice.csv";
+		constexpr const char* SERVICEMANAGEMENTOBSERVERS = "files/ServiceManagementObservers.csv";
+		constexpr const char* PAYMENTMANAGEMENTOBSERVERS = "files/PaymentManagementObservers.csv";
+		constexpr const char* INVENTORYMANAGEMENTOBSERVERS = "files/InventoryManagementObservers.csv";
+	}
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Enums.h

@@ -24,7 +24,6 @@ namespace util
 
 	enum class ServiceJobStatus
 	{
-        PENDING,
 		STARTED,
 		COMPLETED
 	};
@@ -126,8 +125,6 @@ namespace util
             return "STARTED";
         case ServiceJobStatus::COMPLETED:
             return "COMPLETED";
-        case ServiceJobStatus::PENDING:
-            return "STARTED";
         }
         throw std::invalid_argument("Invalid ServiceJobStatus");
     }
@@ -150,9 +147,9 @@ namespace util
         switch (status)
         {
         case State::ACTIVE:
-            return "STARTED";
+            return "ACTIVE";
         case State::INACTIVE:
-            return "COMPLETED";
+            return "INACTIVE";
         }
         throw std::invalid_argument("Invalid State");
     }
@@ -163,7 +160,7 @@ namespace util
         {
             return State::ACTIVE;
         }
-        if (value == "COMPLETED")
+        if (value == "INACTIVE")
         {
             return State::INACTIVE;
         }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/FileHelper.h

@@ -0,0 +1,79 @@
+/*
+File: FileHelper.h
+Description: Provides utility functions for loading and saving records
+             from and to CSV-like text files. Ensures files are created
+             if missing and supports simple record persistence.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#pragma once
+#include <fstream>
+#include <string>
+#include <stdexcept>
+#include "Vector.h"
+
+namespace util
+{
+    /*
+    Function: loadRecords
+    Description: Loads records from a given file path into a vector of strings.
+                 Skips the header line if present. Creates the file if it does not exist.
+    Parameters:
+        - filePath: const std::string&, path to the file
+    Returns:
+        - util::Vector<std::string>: Vector containing all records (excluding header)
+    Throws:
+        - None (creates file if missing)
+    */
+    inline util::Vector<std::string> loadRecords(const std::string& filePath)
+    {
+        util::Vector<std::string> records;
+        std::ifstream file(filePath);
+        if (!file.is_open())
+        {
+            std::ofstream newFile(filePath);
+            newFile.close();
+            file.open(filePath);
+        }
+        std::string line;
+        bool isHeader = true;
+        while (std::getline(file, line))
+        {
+            if (isHeader)
+            {
+                isHeader = false;
+                continue;
+            }
+            records.push_back(line);
+        }
+        return records;
+    }
+
+    /*
+    Function: saveRecords
+    Description: Saves records to a given file path. Overwrites existing content
+                 and writes a header line followed by all records.
+    Parameters:
+        - filePath: const std::string&, path to the file
+        - records: const util::Vector<std::string>&, vector of records to save
+    Returns:
+        - void
+    Throws:
+        - std::runtime_error if the file cannot be opened for writing
+    */
+    inline void saveRecords(const std::string& filePath, const util::Vector<std::string>& records)
+    {
+        std::ofstream file(filePath, std::ios::trunc);
+        if (!file.is_open())
+        {
+            throw std::runtime_error("Failed to open file " + filePath);
+        }
+        file << "Values" << '\n';
+        int numberOfRecords = records.getSize();
+        for (int index = 0; index < numberOfRecords; index++)
+        {
+            file << records[index] << '\n';
+        }
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/FileManager.h

@@ -0,0 +1,116 @@
+/*
+File: FileManager.h
+Description: Declares and implements a generic FileManager template class for
+			 loading and saving objects to and from files. Uses serialization
+			 and deserialization methods defined in the object type T.
+			 Provides persistence support for system entities such as Users,
+			 Services, InventoryItems, etc.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#pragma once
+#include <stdexcept>
+#include <fstream>
+#include "Vector.h"
+#include "Map.h"
+
+namespace util
+{
+	template <typename T> using objects = util::Map<std::string, T*>;
+
+	template <typename T>
+	class FileManager
+	{
+	private:
+		std::string m_filePath;
+	public:
+		FileManager() : m_filePath("") {}
+		FileManager(const std::string& filePath) : m_filePath(filePath) {}
+		objects<T> load();
+		void save(const objects<T>&);
+	};
+
+	/*
+	Function: load
+	Description: Loads records from the file into a map of objects.
+				 Skips the header line, deserializes each record into an object of type T,
+				 and stores them in a map keyed by object ID.
+	Parameters:
+		- None
+	Returns:
+		- util::Map<std::string, T*> containing deserialized objects
+	Throws:
+		- std::runtime_error if deserialization fails for any record
+	*/
+	template <typename T>
+	objects<T> FileManager<T>::load()
+	{
+		objects<T> records;
+		std::ifstream file(m_filePath);
+		if (!file.is_open())
+		{
+			std::ofstream newFile(m_filePath);
+			newFile.close();
+			file.open(m_filePath);
+		}
+		util::Vector<std::string> lines;
+		std::string line;
+		while (std::getline(file, line))
+		{
+			lines.push_back(line);
+		}
+		int numberOfLines = lines.getSize();
+		bool isHeader = true;
+		for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
+		{
+			const auto& record = lines[lineIndex];
+			if (isHeader)
+			{
+				isHeader = false;
+				continue;
+			}
+			auto object = T::deserialize(record);
+			if (!object)
+			{
+				throw std::runtime_error("Failed to deserialize record");
+			}
+			records[object->getId()] = object;
+		}
+		return records;
+	}
+
+	/*
+	Function: save
+	Description: Saves records to the file. Serializes each object of type T into a string,
+				 writes a header line, and then writes all serialized records to the file.
+	Parameters:
+		- records: const util::Map<std::string, T*>&, map of objects to save
+	Returns:
+		- void
+	Throws:
+		- std::runtime_error if the file cannot be opened for writing
+	*/
+	template <typename T>
+	void FileManager<T>::save(const objects<T>& records)
+	{
+		util::Vector<std::string> lines;
+		lines.push_back(T::getHeaders());
+		int numberOfRecords = records.getSize();
+		for (int recordIndex = 0; recordIndex < numberOfRecords; recordIndex++)
+		{
+			const auto& record = records.getValueAt(recordIndex);
+			lines.push_back(record->serialize());
+		}
+		std::ofstream file(m_filePath, std::ios::trunc);
+		if (!file.is_open())
+		{
+			throw std::runtime_error("Failed to open file " + m_filePath);
+		}
+		int numberOfLines = lines.getSize();
+		for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
+		{
+			file << lines[lineIndex] << '\n';
+		}
+	}
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/InputHelper.h

@@ -34,7 +34,7 @@ namespace util
 
     /*
      * Function: read
-     * Description: Reads a line of text input from console into a string.
+     * Description: Reads a line of text input from console into a string and cleans it up.
      * Parameters:
      *     value - reference to a string where the input will be stored
      * Returns:
@@ -43,6 +43,15 @@ namespace util
     inline void read(std::string& value)
     {
         std::getline(std::cin >> std::ws, value);
+        std::string cleanedValue;
+        for (int index = 0; index < value.length(); index++)
+        {
+            if (value[index] != ',')
+            {
+                cleanedValue += value[index];
+            }
+        }
+        value = cleanedValue;
     }
 
     /*

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/StringHelper.h

@@ -0,0 +1,36 @@
+/*
+File: StringHelper.h
+Description: Provides utility functions for extracting numeric values from strings.
+             Useful for parsing IDs, codes, or mixed alphanumeric inputs where
+             digits need to be isolated and converted into integers.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#include <cctype>
+#include <string>
+
+namespace util
+{
+    /*
+    Function: extractNumber
+    Description: Extracts all digits from the given string and converts them into an integer.
+                 Ignores non-digit characters. For example, "abc123xyz" returns 123.
+    Parameters:
+        - input: const std::string&, the input string containing digits and/or other characters
+    Returns:
+        - int: The integer value formed by concatenating all digits in the string
+    */
+    inline int extractNumber(const std::string& input)
+    {
+        int result = 0;
+        for (char character : input)
+        {
+            if (std::isdigit(static_cast<unsigned char>(character)))
+            {
+                result = result * 10 + (character - '0');
+            }
+        }
+        return result;
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/utilities/Utility.h

@@ -0,0 +1,63 @@
+/*
+File: ObserversHelper.h
+Description: Provides utility functions for loading and saving observers
+             in the notification management system. Ensures that observer
+             IDs are validated against existing users in the datastore
+             before attaching them to the notification service.
+Author: Trenser
+Date: 22-May-2026
+*/
+
+#pragma once
+#include "NotificationManagementService.h"
+#include "FileHelper.h"
+#include "DataStore.h"
+
+namespace util
+{
+    /*
+    Function: loadObservers
+    Description: Loads observer IDs from a file and attaches the corresponding users
+                 to the notification management service. Validates that each observer ID
+                 exists in the datastore before attaching.
+    Parameters:
+        - filePath: const std::string&, path to the file containing observer IDs
+        - service: NotificationManagementService*, pointer to the notification service
+        - dataStore: DataStore&, reference to the datastore containing users
+    Returns:
+        - void
+    Throws:
+        - std::runtime_error if an observer ID is invalid (not found in datastore)
+    */
+    inline void loadObservers(const std::string& filePath, NotificationManagementService* service, DataStore& dataStore)
+    {
+        auto observerIDs = util::loadRecords(filePath);
+        auto& users = dataStore.getUsers();
+        for (int index = 0; index < observerIDs.getSize(); index++)
+        {
+            const std::string& observerID = observerIDs[index];
+            int userIndex = users.find(observerID);
+            if (userIndex == -1)
+            {
+                throw std::runtime_error("Invalid Observer ID");
+            }
+            service->attach(users.getValueAt(userIndex));
+        }
+    }
+
+    /*
+    Function: saveObservers
+    Description: Saves the current observer IDs from the notification management service
+                 to a file for persistence.
+    Parameters:
+        - filePath: const std::string&, path to the file where observer IDs will be saved
+        - service: NotificationManagementService*, pointer to the notification service
+    Returns:
+        - void
+    */
+    inline void saveObservers(const std::string& filePath, NotificationManagementService* service)
+    {
+        auto observerIDs = service->getObserverIDs();
+        util::saveRecords(filePath, observerIDs);
+    }
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/AdminMenu.cpp

@@ -1,12 +1,6 @@
-#include <iomanip>
 #include "AdminMenu.h"
-#include "Service.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
-#include "ServiceBooking.h"
-#include "Enums.h"
-#include "Service.h"
-#include "InventoryItem.h"
 
 void AdminMenu::showMenu()
 {
@@ -62,368 +56,16 @@ void AdminMenu::checkStockAvailability()
 {
 }
 
-/*
-Function: listServiceBookings (static helper)
-Description: Lists all pending service bookings and maps them to indices for selection.
-Parameters:
-	- currentBookings: util::Map<std::string, const ServiceBooking*>&, current bookings
-	- bookingsSize: int&, number of bookings
-	- serviceBookingsMap: util::Map<int, const ServiceBooking*>&, map of indexed bookings
-Returns:
-	- bool: True if pending services exist, False otherwise
-*/
-static bool listServiceBookings(util::Map<std::string, const ServiceBooking*>& currentBookings, int& bookingsSize, util::Map<int, const ServiceBooking*>& serviceBookingsMap)
-{
-	int currentIndex = 1;
-	bool hasPendingService = false;
-	std::cout << std::left
-		<< std::setw(10) << "Index"
-		<< std::setw(10) << "ID"
-		<< std::setw(12) << "Status"
-		<< std::setw(12) << "CustID"
-		<< std::setw(20) << "Customer"
-		<< std::setw(15) << "VehicleNo"
-		<< std::setw(15) << "Brand"
-		<< std::setw(15) << "Model"
-		<< std::setw(20) << "Technician"
-		<< std::setw(15) << "TechID"
-		<< std::endl;
-	for (int iterator = 0; iterator < bookingsSize; iterator++)
-	{
-		const ServiceBooking* currentBooking = currentBookings.getValueAt(iterator);
-		if (currentBooking && currentBooking->getStatus() == util::ServiceJobStatus::PENDING)
-		{
-			hasPendingService = true;
-			std::cout << std::left
-				<< std::setw(10) << currentIndex
-				<< std::setw(10) << currentBooking->getId()
-				<< std::setw(12) << util::getServiceJobStatusString(currentBooking->getStatus())
-				<< std::setw(12) << currentBooking->getCustomerId()
-				<< std::setw(20) << currentBooking->getCustomer()->getName()
-				<< std::setw(15) << currentBooking->getVehicleNumber()
-				<< std::setw(15) << currentBooking->getVehicleBrand()
-				<< std::setw(15) << currentBooking->getVehicleModel()
-				<< std::setw(20) << (currentBooking->getAssignedTechnician() == nullptr ? "Null" : currentBooking->getAssignedTechnician()->getName())
-				<< std::setw(15) << (currentBooking->getAssignedTechnicianId().empty() ? "Null" : currentBooking->getAssignedTechnicianId())
-				<< std::endl;
-			serviceBookingsMap.insert(currentIndex++, currentBooking);
-		}
-	}
-	if (!hasPendingService)
-	{
-		std::cout << "No pending service available." << std::endl;
-		return false;
-	}
-	return true;
-}
-
-/*
-Function: selectPendingServiceBookings (static helper)
-Description: Allows selection of a pending service booking by index.
-Parameters:
-	- serviceBookingsMap: util::Map<int, const ServiceBooking*>&, map of indexed bookings
-Returns:
-	- const ServiceBooking*: Pointer to the selected booking, or nullptr if invalid
-*/
-static const ServiceBooking* selectPendingServiceBookings(util::Map<int, const ServiceBooking*>& serviceBookingsMap)
-{
-	int userInputIndex;
-	std::cout << "Enter a valid service index: ";
-	util::read(userInputIndex);
-	if (serviceBookingsMap.find(userInputIndex) != -1)
-	{
-		return serviceBookingsMap.getValueAt(userInputIndex);
-	}
-	else
-	{
-		std::cout << "Enter a valid index.";
-		return nullptr;
-	}
-}
-
-/*
-Function: listAvailableTechnicians (static helper)
-Description: Lists all available technicians and maps them to indices for selection.
-Parameters:
-	- currentAvailableTechnicians: util::Map<std::string, const User*>, available technicians
-	- numberOfTechnicians: int, number of technicians
-	- currentAvailableTechniciansMap: util::Map<int, const User*>&, map of indexed technicians
-Returns:
-	- void
-*/
-static void listAvailableTechnicians( util::Map<std::string, const User*> currentAvailableTechnicians, int numberOfTechnicians, util::Map<int, const User*>& currentAvailableTechniciansMap)
-{
-	bool hasTechnicians = false;
-	int currentIndex = 1;
-	std::cout << std::left
-		<< std::setw(6) << "Index"
-		<< std::setw(15) << "Technician ID"
-		<< std::setw(20) << "Name"
-		<< std::endl;
-	for (int iterator = 0; iterator < numberOfTechnicians; iterator++)
-	{
-		const User* currentTechnician = currentAvailableTechnicians.getValueAt(iterator);
-		if (currentTechnician->getState() == util::State::INACTIVE)
-		{
-			continue;
-		}
-		hasTechnicians = true;
-		std::cout << std::left
-			<< std::setw(6) << currentIndex
-			<< std::setw(15) << currentTechnician->getId()
-			<< std::setw(20) << currentTechnician->getName()
-			<< std::endl;
-		currentAvailableTechniciansMap.insert(currentIndex++, currentTechnician);
-	}
-	if (!hasTechnicians)
-	{
-		std::cout << "No technicians currently available.";
-	}
-}
-
-/*
-Function: selectTechnician (static helper)
-Description: Allows selection of a technician by index.
-Parameters:
-	- currentAvailableTechniciansMap: util::Map<int, const User*>&, map of indexed technicians
-Returns:
-	- const User*: Pointer to the selected technician, or nullptr if invalid
-*/
-static const User* selectTechnician(util::Map<int, const User*>& currentAvailableTechniciansMap)
-{
-	int userInputIndex;
-	util::read(userInputIndex);
-	if (currentAvailableTechniciansMap.find(userInputIndex) != -1)
-	{
-		return currentAvailableTechniciansMap.getValueAt(userInputIndex);
-	}
-	else
-	{
-		std::cout << "Enter a valid index.";
-		return nullptr;
-	}
-}
-
-/*
-Function: assignJob
-Description: Allows the admin to assign pending service bookings to available technicians.
-			 Creates job cards for selected services.
-Parameters:
-	- None
-Returns:
-	- void
-*/
 void AdminMenu::assignJob()
 {
-	util::clear();
-	std::string selectedService;
-	bool hasPendingService = false;
-	auto currentBookings = m_controller.getServiceBookings();
-	auto availableTechnicians = m_controller.getUsers(util::UserType::TECHNICIAN);
-	int bookingsSize = currentBookings.getSize();
-	util::Map<int, const ServiceBooking*> serviceBookingsMap;
-	util::Map<int, const User*> currentAvailableTechniciansMap;
-	if (listServiceBookings(currentBookings, bookingsSize, serviceBookingsMap))
-	{
-		const ServiceBooking* selectedService = selectPendingServiceBookings(serviceBookingsMap);
-		if (selectedService)
-		{
-			if (availableTechnicians.getSize() != 0)
-			{
-				listAvailableTechnicians(availableTechnicians, availableTechnicians.getSize(), currentAvailableTechniciansMap);
-				const User* selectedTechnician = selectTechnician(currentAvailableTechniciansMap);
-				if (selectedTechnician)
-				{
-					auto& servicesInBooking = selectedService->getServices();
-					for (int iterator = 0; iterator < servicesInBooking.getSize(); iterator++)
-					{
-						m_controller.createJobCard(selectedService->getId(), selectedTechnician->getId(), servicesInBooking.getValueAt(iterator)->getId());
-					}
-				}
-			}
-			else
-			{
-				std::cout << "No technicians are currently available.";
-			}
-		}
-	}
-
 }
 
-/*
-Function: selectInventoryItems (static helper)
-Description: Allows selection of inventory items by index for creating a service.
-Parameters:
-	- currentInventoryItems: util::Map<std::string, const InventoryItem*>&, available inventory items
-	- selectedInventoryItems: util::Vector<std::string>&, vector to store selected item IDs
-Returns:
-	- void
-*/
-static void selectInventoryItems(util::Map<std::string, const InventoryItem*>& currentInventoryItems, util::Vector<std::string>& selectedInventoryItems)
-{
-	bool doRun = true, hasInventoryItems = false;
-	util::Map<int, const InventoryItem*> currentInventoryMap;
-	int currentIndex = 1;
-	int choice;
-	if (currentInventoryItems.getSize() == 0)
-	{
-		std::cout << "Inventory empty.";
-	}
-	while (doRun)
-	{
-		bool hasInventoryItems = false;
-		int currentIndex = 1;
-		currentInventoryMap.clear();
-		std::cout << std::left
-			<< std::setw(6) << "Index"
-			<< std::setw(12) << "Item ID"
-			<< std::setw(20) << "Part Name"
-			<< std::setw(10) << "Price"
-			<< std::setw(10) << "Quantity"
-			<< std::endl;
-		for (int iterator = 0; iterator < currentInventoryItems.getSize(); iterator++)
-		{
-			const InventoryItem* currentInventoryItem = currentInventoryItems.getValueAt(iterator);
-			if (currentInventoryItem->getState() == util::State::INACTIVE)
-			{
-				continue;
-			}
-			std::cout << std::left
-				<< std::setw(6) << currentIndex
-				<< std::setw(12) << currentInventoryItem->getId()
-				<< std::setw(20) << currentInventoryItem->getPartName()
-				<< std::setw(10) << currentInventoryItem->getPrice()
-				<< std::setw(10) << currentInventoryItem->getQuantity()
-				<< std::endl;
-
-			hasInventoryItems = true;
-			currentInventoryMap.insert(currentIndex++, currentInventoryItem);
-		}
-		if (!hasInventoryItems)
-		{
-			std::cout << "No items present in the inventory." << std::endl;
-			doRun = false;
-			break;
-		}
-		std::cout << "Select the item (Index) or enter -1 to exit: ";
-		util::read(choice);
-
-		if (choice == -1)
-		{
-			doRun = false;
-		}
-		else if (currentInventoryMap.find(choice) != -1)
-		{
-			selectedInventoryItems.push_back(currentInventoryMap.getValueAt(choice)->getId());
-			std::cout << "Item added successfully." << std::endl;
-		}
-		else
-		{
-			std::cout << "Enter a valid integer." << std::endl;
-		}
-	}
-}
-
-/*
-Function: createService
-Description: Allows the admin to create a new service by selecting inventory items and specifying labor cost.
-Parameters:
-	- None
-Returns:
-	- void
-*/
 void AdminMenu::createService()
 {
-	util::clear();
-	std::string serviceName;
-	double labourCost;
-	std::cout << "Enter the service name: ";
-	util::read(serviceName);
-	util::Map<std::string, const InventoryItem*> currentInventoryItems = m_controller.getInventoryItems();
-	util::Vector<std::string> selectedInventoryItems;
-	selectInventoryItems(currentInventoryItems,selectedInventoryItems);
-	std::cout << "Enter the labour cost: ";
-	util::read(labourCost);
-    m_controller.createService(serviceName, selectedInventoryItems, labourCost);
-    std::cout << "Service created sucessfully.\n";
 }
 
-/*
-Function: selectServicesToRemove (static helper)
-Description: Allows selection of a service to remove by index.
-Parameters:
-	- currentServices: util::Map<std::string, const Service*>, available services
-Returns:
-	- std::string: ID of the selected service, or empty string if invalid
-*/
-static std::string selectServicesToRemove(util::Map<std::string, const Service*> currentServices)
-{
-    util::Map<int, const Service*> currentServicesMap;
-    bool hasServices = false;
-    int currentIndex = 1, choice;
-    std::cout << std::left
-        << std::setw(6) << "Index"
-        << std::setw(12) << "Service ID"
-        << std::setw(20) << "Name"
-        << std::setw(10) << "Labor Cost"
-        << std::endl;
-    for (int iterator = 0; iterator < currentServices.getSize(); iterator++)
-    {
-        const Service* currentService = currentServices.getValueAt(iterator);
-        if (currentService->getState() == util::State::INACTIVE)
-        {
-            continue;
-        }
-        std::cout << std::left
-            << std::setw(6) << currentIndex
-            << std::setw(12) << currentService->getId()
-            << std::setw(20) << currentService->getName()
-            << std::setw(10) << currentService->getLaborCost()
-            << std::endl;
-        hasServices = true;
-        currentServicesMap.insert(currentIndex++, currentService);
-    }
-    if (!hasServices)
-    {
-        std::cout << "No services currently available." << std::endl;
-        return "";
-    }
-    std::cout << "Enter your choice: ";
-    util::read(choice);
-    if (currentServicesMap.find(choice) != -1)
-    {
-        return currentServicesMap.getValueAt(currentServicesMap.find(choice))->getId();
-    }
-    else
-    {
-        std::cout << "Invalid choice." << std::endl;
-        return "";
-    }
-}
-
-/*
-Function: removeService
-Description: Allows the admin to remove an existing service by selecting from available services.
-Parameters:
-	- None
-Returns:
-	- void
-*/
 void AdminMenu::removeService()
 {
-	util::clear();
-	std::string selectedServiceID;
-	util::Map<std::string, const Service*> currentServices = m_controller.getServices();
-	selectedServiceID = selectServicesToRemove(currentServices);
-	if (selectedServiceID != "")
-	{
-		m_controller.removeService(selectedServiceID);
-		std::cout << "Service removed sucessfully.";
-	}
-	else
-	{
-		std::cout << "Failed  to remove service.";
-	}
 }
 
 void AdminMenu::addTechnician()

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/CustomerMenu.cpp

@@ -1,10 +1,6 @@
-#include <iomanip>
 #include "CustomerMenu.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
-#include "User.h"
-#include "ServiceBooking.h"
-#include "Enums.h"
 
 void CustomerMenu::showMenu()
 {
@@ -55,55 +51,8 @@ void CustomerMenu::selectComboPackage()
 {
 }
 
-/*
-Function: viewServiceHistory
-Description: Displays the customer’s past service bookings in tabular format,
-             including booking ID, technician, vehicle details, discount percentage, and status.
-Parameters:
-    - None
-Returns:
-    - void
-*/
 void CustomerMenu::viewServiceHistory()
 {
-	util::clear();
-	bool hasServiceHistory = false;
-	const User* currentUser = m_controller.getAuthenticatedUser();
-	std::string currentUserID = currentUser->getId();
-	util::Map<std::string, const ServiceBooking*> serviceBookingsByCurrentUser = m_controller.getServiceBookingsByUser(currentUserID);
-    if (serviceBookingsByCurrentUser.getSize() != 0)
-    {
-        std::cout << std::left
-            << std::setw(12) << "Booking ID"
-            << std::setw(20) << "Technician"
-            << std::setw(15) << "Vehicle Brand"
-            << std::setw(15) << "Vehicle Number"
-            << std::setw(15) << "Vehicle Model"
-            << std::setw(10) << "Discount %"
-            << std::setw(12) << "Status"
-            << std::endl;
-        for (int iterator = 0; iterator < serviceBookingsByCurrentUser.getSize(); iterator++)
-        {
-            const ServiceBooking* currentBooking = serviceBookingsByCurrentUser.getValueAt(iterator);
-            std::string technicianName = currentBooking->getAssignedTechnician() == nullptr
-                ? "Not Assigned"
-                : currentBooking->getAssignedTechnician()->getName();
-            std::cout << std::left
-                << std::setw(12) << currentBooking->getId()
-                << std::setw(20) << technicianName
-                << std::setw(15) << currentBooking->getVehicleBrand()
-                << std::setw(15) << currentBooking->getVehicleNumber()
-                << std::setw(15) << currentBooking->getVehicleModel()
-                << std::setw(10) << currentBooking->getDiscountPercentage()
-                << std::setw(12) << util::getServiceJobStatusString(currentBooking->getStatus())
-                << std::endl;
-            hasServiceHistory = true;
-        }
-    }
-    if (!hasServiceHistory)
-    {
-        std::cout << "No history available." << std::endl;
-    }
 }
 
 void CustomerMenu::completePayments()

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/TechnicianMenu.cpp

@@ -1,10 +1,6 @@
-#include <iomanip>
 #include "TechnicianMenu.h"
 #include "InputHelper.h"
 #include "OutputHelper.h"
-#include "JobCard.h"
-#include "Enums.h"
-#include "Service.h"
 
 void TechnicianMenu::showMenu()
 {
@@ -35,86 +31,8 @@ bool TechnicianMenu::handleOperation(int choice)
 	return false;
 }
 
-/*
-Function: selectJobCardToComplete (static helper)
-Description: Lists all incomplete job cards assigned to the technician and allows selection by index.
-Parameters:
-    - assignedJobCards: util::Map<std::string, const JobCard*>&, job cards assigned to the technician
-    - incompleteJobCards: util::Map<int, const JobCard*>&, map of incomplete job cards indexed for selection
-Returns:
-    - std::string: ID of the selected job card, or empty string if none selected
-*/
-static std::string selectJobCardToComplete(util::Map<std::string, const JobCard*>& assignedJobCards, util::Map<int, const JobCard*>& incompleteJobCards)
-{
-    int currentIndex = 1;
-    int choice;
-    bool hasIncompleteJobCard = false;
-    std::cout << std::left
-        << std::setw(6) << "Index"
-        << std::setw(12) << "BookingID"
-        << std::setw(12) << "JobID"
-        << std::setw(20) << "ServiceName"
-        << std::setw(12) << "ServiceID"
-        << std::endl;
-    for (int iterator = 0; iterator < assignedJobCards.getSize(); iterator++)
-    {
-        const JobCard* currentJobCard = assignedJobCards.getValueAt(iterator);
-        if (currentJobCard && (currentJobCard->getStatus() == util::ServiceJobStatus::STARTED))
-        {
-            std::cout << std::left << std::setw(6) << currentIndex
-                << std::setw(12) << currentJobCard->getBookingId()
-                << std::setw(12) << currentJobCard->getId()
-                << std::setw(20) << currentJobCard->getService()->getName()
-                << std::setw(12) << currentJobCard->getServiceId()
-                << std::endl;
-            hasIncompleteJobCard = true;
-            incompleteJobCards.insert(currentIndex++, currentJobCard);
-        }
-    }
-    if (!hasIncompleteJobCard)
-    {
-        std::cout << "No pending jobs are present.\n";
-        return "";
-    }
-    std::cout << "Select the Job Card to complete (Index): ";
-    util::read(choice);
-    int selectedJobCardIndex = incompleteJobCards.find(choice);
-    if (selectedJobCardIndex != -1)
-    {
-        const JobCard* selectedJobCard = incompleteJobCards.getValueAt(selectedJobCardIndex);
-        return selectedJobCard->getId();
-    }
-    else
-    {
-        std::cout << "Invalid choice.\n";
-        return "";
-    }
-}
-
-/*
-Function: completeJob
-Description: Allows the technician to mark a selected job card as completed.
-             Validates selection and updates job status through the controller.
-Parameters:
-    - None
-Returns:
-    - void
-*/
 void TechnicianMenu::completeJob()
 {
-	util::Map<std::string, const JobCard*> assignedJobCards = m_controller.getJobCardsByUser();
-	util::Map<int, const JobCard*> incompleteJobCards;
-	std::cout << "Jobs to be completed.\n";
-	std::string selectedJobID = selectJobCardToComplete(assignedJobCards, incompleteJobCards);
-	if (selectedJobID == "")
-	{
-		std::cout << "Failed to complete the job.\n";
-	}
-	else
-	{
-		m_controller.completeJob(selectedJobID);
-		std::cout << "Job marked as completed.\n";
-	}
 }
 
 void TechnicianMenu::viewNotifications()

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/UserInterface.cpp

@@ -4,6 +4,7 @@
 
 void UserInterface::run()
 {
+	m_controller.loadSystemData();
 	bool isMenuActive = true;
 	while (isMenuActive)
 	{
@@ -24,6 +25,7 @@ void UserInterface::run()
 			util::pressEnter();
 		}
 	}
+	m_controller.saveSystemData();
 }
 
 bool UserInterface::handleOperation(int choice)